I want this too. I tried to do a hogger raid, and due to the creation order (didn't know about it at the time) I couldn't get my "main" to be party1. Only when I was the creator of the raid could my macros work. I really don't want to go back to using character names in macros, because it limited my ability to swap out lead characters (my booster, or my equal level char, or in one case another player, when I was just a "dps train" for a warrior) I don't want to get to 70 and get invited to a kara raid and have to hold them up while I change my macros. I can't re-roll my main because it was created long before I started boxing.

Is there any other way to dynamically set a "lead" character for targeting within a raid? I like my party1 macros, and my party1target and party1targettarget macros.