Yeah this will be a pain but the developers usually post on their websites dates and times there gonna be online.
They usually do this for about 2 weeks for the achivement to circulate enough. Then it's a matter of joining a random game watching a buddy get shot fix 'em up get the cheevo and spread the cheevo to your friends or get your friend to do this and bobs your uncle.
Got it. It was pretty cool to get. I got it by shooting the guy in my FT in the foot and then healing him. Blue on Blue for an achievement. Helped others get it the same way. Worth a round in the leg to help out someone I figure.