/script SetRaidTarget("target", n)

where n is:

1 Yellow 4-point Star
2 Orange Circle
3 Purple Diamond
4 Green Triangle
5 White Crescent Moon
6 Blue Square
7 Red "X" Cross
8 White Skull

use this together with focus on my mages, priestkey sets icon, mage key sets focus

ctrl F1 set star with priest, set focus on mage1
ctrl F2 set circle with priest, set focus on mage2
and so on