Does the medic promotion stack?

The medic promotion for land units increases the heal rate of that unit, and those in adjacent hexes.

I've just had a thought, but unfortunately am not at home to check, so thought I'd ask before I forget about it: Does the effect of the promotion stack?
If I have three injured units with the promotion and place them in a triangle formation (so they are each adjacent to the other two), and fortify them all to heal, will they each receive a bonus of:

• +3 (+1 from themselves and +1 from each of the other 2 units)
• +2 (+1 from themselves and +1 from a non-stacking adjacent effect)
• +1 (+1 from themselves; no stacking at all)
• Something else?
• Imagine the 7 unit circle formation :D 3 adjacent units for the 6 units on the edge and 6 for the 1 in the center. Commented Oct 8, 2010 at 14:55
• @alex Actually, when it came to mind I was thinking of some sort of arrangement with a citadel at a choke point, with two or three medic units in the places "behind" it... Commented Oct 8, 2010 at 14:59