Ableton live RACKS: is there an equivalent, or better, functionality available in reaper?

I’m an ableton live user (only because I received live bundled with my keyboard) but now i’m considering trying out reaper out of frustration with various design decisions in live which those guys are simply unwilling to fix, so i have a couple of questions concerning if some of live’s Rack features can be implemented somehow in reaper.

First a few words about ableton live’s Racks.

In live, racks are essentially containers which can host multiple parallel "device chains", where a "device" is a midi/instrument/effect (depending on the type of rack), and a "device chain" is a series of devices through with the sound or midi messages pass through and/or are transformed (depending on the type of rack – midi/instrument/effect).

The above can be illustrated as follows:

Rack { deviceChain || deviceChain || ... }

where:

deviceChain [ Device > Device > ... ]

Each rack container can have UP TO 8 control knobs (yes, max eight!) which can be mapped to any controls of any device directly contained in the rack, e.g. if a rack contains, inside one of its device chains, a series of N devices, then any control of any of the N devices can be mapped to one of the rack’s 8 knobs; this can be illustrated as follows:

Rack(rackControls) { [Device(deviceControls) > ...] || ...}

In the above you can directly map any deviceControl to any rackControl, i.e.:

deviceControl ---mappedTo---> rackControl

However, if one of the devices in a chain is itself a rack (i.e. we thus have a rack inside a rack chain), and said “inner rack” itself contains other devices, then the controls of the devices inside the "rack within a rack" cannot be mapped directly to the knobs of the "outer" rack; instead, they need to be mapped to the controls of the "inner" rack which contains the device, and then the controls of the inner rack can be mapped to the controls of the "outer" rack (i.e. a control of a device contained in a "rack inside a rack" cannot be directly mapped to the controls of the outer rack – they can only be mapped to the controls of the outer rack indirectly, by means of the knobs of the inner rack); this can be illustrated as follows for an OuterRack containing a single chain with an InnerRack which, in turn, contains a single Device:

OuterRack(outerControls) { [InnerRack(innerControls) { [Device(deviceControls)]}]}

In the above, you must map a deviceControl to a outerControl INDIRECTLY via a innerControl, i.e.:

deviceControl ---mappedTo---> innerControl ---mappedTo---> outerControl

And now my problem with this arrangement: the 8 knob limit on a rack in live is ridiculous, you immediately run out of rack buttons even if a rack has only one chain with several devices for which you want to map controls on the container rack’s controls, but the situation becomes disastrous if the rack actually holds multiple parallel chains which, in turn, each contain several devices, and you need to make available some of the controls of the various devices (in all the rack’s chains) at the "top level" of the container rack.

So this brings me to my first question:

Is there such a thing as a container in Reaper (i.e. a method of grouping together a number of parallel processing chains and provide them with a unified set of controls such that said group can then be reused as a stand-alone device), and, if yes, is there a limit to how many controls it can hold (which controls need to be mappable to the controls of any of the devices contained inside the container)?

And now, before I get to my second question, a bit more on ableton live’s racks:

In ableton live the output of the parallel chains contained inside a rack (i.e. Rack { deviceChain1 || deviceChain2 || ...}) can be “mixed” in several ways: namely, live’s racks provide a volume control for each chain inside a rack via which the volume of said chain can be adjusted based on several criteria, namely the note that the chain is playing, the velocity of the key that’s entering the chiain, and an option which is essentially equivalent to a mixer (well, that’s not a 100% accurate nor complete description of this live feature, but this is the basic idea).

For example, you can create a three-chain “instrument rack” in live with one chain containing a violin, another chain containing a cello, and yet another chain containing a bass; then, using said “rack mixer” functionality, you can e.g. mix the volumes of the 3 chains based on the note the rack is playing, such that the timbre of the note that is being played smoothly shifts from one instrument to another depending on the note:

Note:          c0...c1...c2...c3...c4...c5...c6

Bass volume:  127   64    0    0    0    0    0

Cello volume:   0   64  127  127   64    0    0

Violin volume:  0    0    0    0   64  127  127

So this bring me to my second question:

Is there a Reaper functionality, by any means and in any form, equivalent to or better than Ableton Live’s rack mixers (as described above, i.e. either a container which provides mixing functions based on key velocity, on key note, and on automateable knobs; or anything else which provides such complex mixer functionality)? If yes, then are there also other parameters in reaper that can control the mixing process of parallel chains (i.e. apart from velocity, note, and automateable control knobs)?

Well, I’ll stop here for now, I do have several other questions but it makes no sense to continue with them until I get the answers to the two questions in this post.