The only time they don't work together is the events are identical I believe, so if you had:

Code:
on *:nick:{ xyz }
on 1:nick:{ abc }


Both events would trigger, because the first one triggers for everyone (*), but the second only triggers for level 1 users.

But if you had:

Code:
on *:nick:{ xyz }
on *:nick:{ abc }


The second wouldn't trigger, and you'd have to combine the two events.