I use this

/cast [@party1,dead][@party2,dead][@party3,dead][@party4,dead]Raise Ally

I swapped out the @party1etc for my actual team player names - since in a battleground it may not be correct. - Making sure my healer was the first one to get res'ed

But like jeepdriver's maybe 'exists' will stop it getting stuck if you're out of range or something I don't know.