I don't know exactly the difference between those two? What are the most commons use for those ones?
For example, what are the difference between these sentences?
友達に会った
友達に集まった
友達に集まった does not make any sense. It should be 友達が集まった. But even then the meaning is not the same.
会う : meet
集まる : gather
友達が集まった。 : my friends gathered
友達に会った。 : I met my friends
They aren't related at all.