If you're certain that the load on 2 particular branches is that light, there should be no reason you can't combine them with a pigtail. I wouldn't do it as regular practice though. Art 373-8 ('99 code. sorry, I don't feel like going to my truck) allows the splice.
Remember some breaker terminals will accomodate 2 terminations. Sq.D QO, for one. And I believe Pushmatics design permits it as well.
