That is possible, with some constraints.

You can use the following commands:

/targetfriend - Cycles through all friendlies near you, grouped with you or not, but never selects you. Same as pressing Ctrl-TAB. Keep in mind this cycles through friendly pets and totems as well.

/targetparty - Cycles through your party members, but never selects you.

/targetraid - Cycles through your raid members, but never selects you.

On my pally + shammies setup I have the following macro on my pally:

Code:
/cast [mod:ctrl,target=player] Cleanse
/stopmacro [mod:ctrl]
/targetparty
/cast Cleanse
Since dispelling spells dont activate the global cooldown if theres nothing to dispel, this can be spam clicked.

If one of my shammies has a debuff (except those damn curses :cursing: ) I just spam click the button until it gets dispelled.
If my pally has a debuff I hit ctrl + the button.

Unfortunatly, you can only check for one spell per macro, so if you have a non-pally dispeller, you'll need a seperate macro/button for each dispel type (one of poisons and one for curses for a druid, etc...).

I think this is close to what you're looking for.