I think the most important decision is whether you want to control via keyboard or mouse.
Lets break down each of the steps that needs to happen:
First, your FC (one of your DPS guys) broadcasts the target.
Second, each of your characters locks the target.
Third, each of your characters shoots the target.
If doing it by keyboard, it might look like this:
First, your FC broadcasts the target.
Second:
-Your FC locks the target by ctrl-clicking on the broadcast window. You leave your mouse hovering in this spot.
-You hit a key to switch to the second account.
-You ctrl-click again to lock the target on the second account.
-Hit key to switch accounts again, repeat process until all 10 dps have locked the target.
Third:
-Your FC activates his grouped weapons with the F1 key.
-Your FC presses a key to switch to a second account, and you hit F1 again
OR
-Your FC activates his grouped weapons with the F1 key.
-You have F1 set up to round robin, so when you press it a second time, it goes to account two, and so on til all the DPS have activated weapons.
Note: I'm aware that you could combine locking with pre-activating weapons, this way just makes it easier to explain.
But what if you want to do it by mouse actions? Then you set up some fancy videoFX with dxnothing and repeater regions (i think? the one where your mouse clicks get passed through to the screen being displayed):
First, your FC will broadcast a target. Then your FC will lock that target (ctrl-click on broadcast window).
Second, you ctrl-click on the videoFX for all your other broadcast windows, ideally nice and lined up across your screen to minimize the amount of mouse movement necessary.
Third, you click on all of your modules, which again are hopefully lined up in your videoFX.
example:
http://i.imgur.com/ecqpiHV.pngThere are ways to combine these two methods, and lots of people here are way better at this than I am.
Disclaimer: I have no idea if any of this stuff conflicts with CCP's new rules...I don't think it does, but the round robin thing to activate guns might be close enough to the line to cause you trouble.