Can you play in a group with players from other Powers?

I have a friend who has just started playing E:D and he has now got to the point where he is ready to choose his Power allegiance.

I am allied with Edward Mahon and he is planning on allying with either one of the Independent or Federation powers.

Will we still be able to group up and play and are there any "gotchas" besides possibly being attacked by system authority vessels and the like?