if you target via macro, you will not lose your current target (if you're targeting your main). if you use /target, you'll lose your current target, but since its in the macro like [target=playername] it shouldnt change your target.


you can do this:

F1: /cast [target=slave1, nodead, help] Lesser Healing Wave
F2: /cast [target=slave2, nodead, help] Lesser Healing Wave
F3: /cast [target=slave3, nodead, help] Lesser Healing Wave
F4: /cast [target=slave4, nodead, help] Lesser Healing Wave

put these macros in for all four of your shamans and bam. it should work.
the logic for this macro (say F2) is basically... cast lesser healing wave on slave2 if he's not dead and is friendly. but this macro doesnt tell the character to actually "target" the slave, just that the spell goes to the slave.