Getting Mouseover to transfer to slave?

So I'm new to multiboxing and macros. I'm dual-screening two priests and I'm trying to figure out how to get the target=mouseover macro feature to work so that I can have my slave backup heal when I need it. The problem is, I mouseover a portrait on my main and I don't think the cursor position goes through to the second window because the slave isn't recognizing any mouseover target. Does anyone have a fix for this? I know there are other ways I could set up my macros and/or targetting but I was hoping to get the mouseover working because it seems like the easiest solution and the best way to get a backup heal in without losing any of my targets.

You would have too move your mouce over too the other screen, remember it is 2 seperate wows, therefore your best bet would be

/cleartarget

/cast [target=mouceover] blah blab

slave

/cleartarget

/cast [target=focustarget] blah blah

i could be wrong... dont get mad if i am lol