How can I keep mobs from being too close together with /spreadplayers and /execute?

I want to summon multiple Slimes, then make sure that they are never in the same block. (If it’s not possible to keep them from being in the same block, having them be at least 1 block from each other would work too.)

To do this I tried nesting execute commands like this:

execute @e[type=Slime,name=explore1] ~ ~ ~ execute @e[type=Slime,name=explore1,r=0,c=1] ~ ~ ~ spreadplayers ~.5 ~.5 0 1 false @e[type=Slime,name=explore1,r=1,c=1]

But that didn’t work. I also tried

execute @e[type=Slime,name=explore1] ~ ~ ~ spreadplayers ~.5 ~.5 0 1 false @e[type=Slime,name=explore1,c=1,r=0]

I figured the r=0 tag might be off but I also tried with r=1 and it still didn’t work.

The first command groups all the Slimes together and randomly teleports them, and the second command just does nothing.

Any ideas on how to do this?

execute @e[type=Slime,name=explore1] ~ ~ ~ spreadplayers ~ ~ 2 3 false @e[type=Slime,rm=0,r=1,name=explore1]