Probably as ILikeTwins suggests.

RAF your five accounts.
You can have her account RAF linked to one of the accounts that you won't drop when she joins.

Then you can run PvE content without her.
Have the healer type on the account you will drop.
Or the tank type.

Have DPS or hybrids who can DPS & Heal on the four accounts that aren't dropped.



For example:
a: Paladin
b/c/d/e: Shaman

That's a solid PvE team.
And you can drop your Pally, and go with hers for PvP.