It is possible to merge a list of text that are uniqueids from the various sources, and then search for each one to determine if you want to show it or not.
It almost works but there is a bug that means displaying the data doesn’t work all that well.
The issue is that you can’t put a conditional on the field or group, because of the bug.
The way round it is to have a bunch of hidden repeating groups, with lists of uniqueids, and then you can merge THAT. A condition can then be created to determine if something is in a particular list.
Horrible, but it works.
Or badger Bubble to fix the bug that was reported in Dec 17.