I would probably set it up as a Collection project knowing that it will initially be sort of a pain to get going – you’ll have to manually enter all 100 taxa you’d like to include. But once you do that, everything should run automatically for you, bringing in observations of the taxa you set up in the place you specified.
Related discussion here: https://forum.inaturalist.org/t/is-there-an-limit-for-included-or-excluded-taxa-in-a-project/12157