Can you pick up and carry multiple allies with the Bear Allies' Burdens activity of the Skybearer's Belt ikon from the Exemplar class?
It says "At any point you are adjacent to a willing ally during the Stride, you can..." so any time that Condition is met, the effect of "pick that ally up, and you can deposit them into a space adjacent to you at any other point during your movement" is permitted, correct?
I agree with BenT1. The mechanic text is all in the singular. I don't think you can do this with multiple allies at the same time.
But I could do it with multiple allies, one after the other?
Honestly, it's a bit unclear. But for me, everything leads me to believe that it's just one ally. If there were multiple ally, I think they would write it more clearly that you can follow more than one ally, how many allies you can do, if you can do it in sequence, that kind of thing.
In terms of balance, I don't see this being too unfair, you take an ally and leave them in one corner, then another one in another. OK, it can make things easier like flanking and getting out of dangerous terrain, but since leaving an enemy off guard in PF2e is something so trivial that I don't see it as a big problem, and removing allies from dangerous terrain, depending on how the terrain works, can be very damaging to the exemplar itself.
I honestly interpret it as not being allowed and for safety reasons I wouldn't allow it in my games, as it could open up a flank for abuse.
But by RAW it's unclear and it's not something that I see breaking the game, perhaps trivializing some area effects very occasionally.