I'm levelling (Oh so slowly) a lock + priest team.

I've solo played a lock to 70 and pvped at level cap at that time for ages,
The times I was lucky enough to have a healer backing me up I was almost unstoppable.
(that was affliction).


You are all destro so have to plant your feet a bit more but the damage will be fantastic - I will probably go affliction on my group.
Dotting from range, moving to someone else and dotting them up. Self healing a little with siphon life on multiple targets, a bit of healing with haunt. A Curse of exhaustion slowing pursuers down.

I think a priest or a druid is the best suited to a group of locks. I went with the priest as holy nova does damage as well as heals.
And improved shields and divine aegis, pain suppression etc all seemed nice to have.

Take a look at furspheres macro compenium thread. There is a disc priest click macro.
I would bind that on a key that has the main dps macro on the warlocks but that you don't normally use.
Then you can choose to leave the priest out of dealing damage to concentrate on healing, or can have him dishing out damage by pressing another button.