Solution

I think I found the correct rules:

The trick is in creating two subgroups, one for bananas and one for oranges and then creating sub-subgroups for those two subgroups.

You can get subgroups by holding alt (on a Mac) and then clicking the plus sign + (which turns into a pound sign # when holding alt).
This creates a new subrule, allowing you to set the All/Any of the following are true dropdown for that subgroup only.

Importing rules

I've exported the smart collection rules here. To get that back in your LR as a smart collection, follow these steps:

1. Copy the text from the link into a text file
2. Change the extension from .txt to .lrsmcol
3. In LR, right click in the Collections panel and click Import Smart Collection Settings....

4. Select the .lrsmcol file from step 2.

This should re-create the smart collection shown in the top screenshot.