You can currently have multiple copies of the same gem with different supports equipped simultaneously. There have been multiple YouTube videos about this, so it is already a well-known exploit, and we can expect a nerf soon (definitely don't invest a bunch of currency in this strategy). There are many ways to abuse this, like emergency reload and tempest bell, that can trivialize most content. This bug becomes even more abusable in group play (the group can literally stack 5+ bells per person, reflecting insanely strong elemental ailments, as each bell can be specialized to deal a different damage type).
I'm not trying to take any credit here, and I have no clue who discovered the exploit first, but I thought I would get the forum posts started in case anyone has missed this. If you want to check out a YouTube video that features a few potential use cases, I know ds_lily uploaded one recently.