Depends on what you mean by different groups. I'm running seven different groups of characters in my D&D game, but all of them have significant player overlap- there are only four players unique to one group. I also play in two groups; even given that all of the players and the DM of one of them are players in my games, I would count that as a different group than the one I DM. So depending on how you count, either ten, or three, or something in between.
I'm going to split the difference- there are essentially, sort of, 3 groups of players in my various games, so I'll say I am in 5 groups.