If you want them all to dps from the same key then make your isboxer macro like this

Code:
 
!if (character is in "warlocks") /assist tank
!also /cast shadowbolt
!also /kill more stuff
 
!elseif (character is in "mages") /assist tank
!also /make water now!!
!also /kill stuff
At the top tell isboxer to send to all windows and will setup the individual character macros correctly.
It is explained here on the ISboxer wiki.

You basically tell different action target groups to do different things in one "macro". When this configuration gets exported to innerspace it also translates theses "macros" to the WOW addon such that only the mage gets the mage part of the macro and the lock gets the lock part etc. They will all have the same keybind so when you want to dps they will do the correct action/spell.

Hope this helps.