The one I use is a uo macro
use skill
provoke
alternatively you can use uoassit as set up the targets If they will survive each other long enough to get a second or third attempt off
useskill/cast spell
target
target
pause 8000 <---- more if ya lag!
Not sure what your skill is but a pair of rotten corps tend to live plenty long for even a 4th or 5th attempt.
Mostly what I do is run into an area with plenty of my current skill mobs with a precast invisibility. Then pull bars untill I got 10 or so and use my uo macro targeting each as dictated by skill lvl. The 1st target is the most important part of the skill equation so If your mobs are low for you then pick the harder mob as your 1st target for gains. But when your over your head always use the weaker target 1st. Youll have better success
Good luck