First of all, your ulx and ulib are slightly outdated, you can get the latest
here.
As far as I know, the "Team()" function can only be called on one person (I could be wrong). Also, SetTeam() can only be called on the client, so you'd need a check for that.
So, really, I don't think this can be a multi target thing, just try it with one, it would probably be easier anyways.