Hi there, @Namibi… I didn’t want to mess around in your app, so I made an example that I believe does what you described. I have the three option sets you mentioned, and I have list fields on the User data type that link to the option sets. Oh, and if you haven’t already turned on the experimental parentheses feature in your app, well, that’s how I got the brackets to appear in my expressions (just anticipating that question).
With the above setup in place, the repeating group’s data source is simply Search for Users:minus item Current User with no constraints on the search.
Then, I have a disabled input element in the repeating group that shows a sum of the intersects across all three lists.
Finally, here is a text element that displays the activities that the current user and the current cell’s user have in common.
You would have a similar text element for categories and animals, and I hope this helps.
Best…
Mike