I tried something like this and am having problems with the party1, party2, etc. Essentially who ever I use the macro on assumes that they are party1. I solved it by using real names for the focus part.
Code:
/focus Mugnin
etc

It does mean I need extra keys, F1-5 for each party member, tab for follow on the alts. But it also means once a new character is in foreground I can play them as normal, makes quest looting so much easier.

What I really want is to change my cast macros to remove the Unit not Found error message.... I tried:
Code:
#showtooltip
/assist [exists,nodead] focus
/cast <whatever>
But that doesn't seem to work