Changing the clicky heals

[desna]

A couple other healers and I were wondering if there was a relatively painless way to assign/change click heal buttons on the group and raid windows to different spells? My warden's, for instance, has Tunare's Watch on the bar (which makes no sense since it's groupwide) and I could use the botton for, say, Tranquility or a rez.

I don't know much about editing xml files at all, and couldn't find how to do it myself.