Well, I've been known to bark up the wrong tree before, but Latin simul (together, at once, at the same time, as soon as) is related to Sanskrit samas (same) and Greek omos, ama (same). Dutch has samen meaning together, so it's tempting to see the same root and link it with "sammeln", but I don't honestly know.

Come to think of it, Finnish has samalainen meaning "same", so either that's one for the Nostraticists, or came from Germanic. Or just a coincidence.