Repeater regions are essentially the same.

Create a box, drag it over the area where you want things to repeat.
Choose the target, which can be slot (account) numbers, or predefined groups (Action Target Groups).

I like to use ATG's, as you can use mapped keys during play, to manually add or remove toons from the group which receives the click broadcasts.
Also you could mess around with something like this:
- Paladin + 4x Shaman, all Elemental, all in the ATG.
- Mapped Key, switches spec on one shaman to Resto, removes the other three shammies from the ATG, giving you a dedicated healer and dedicated dps.
- Step 2 on the mapped key reverses it all.