FTL Assist isn't full working.

[Vociferate]

I am 4 boxing with IS Boxer, and I created a new team.

Toons A&B when selected and are the HoT character, are working properly and all 4 toons select and attack the target.
Toons C&D do not. They are not being assisted by any of the 3 toons, so they are left there attacking for themselves.

Not sure how to word that any better...

I am trying to figure out why only half the toons are broadcasting the keys properly, and the others simply are not.

[Iceorbz]

Check to make sure they right accounts are being loaded into the right slots.
And also if you have modified the stuff for muting keymaps, ensure that the right keymaps are being turned on and off when you mute or broadcast.

[Lax]

Did you make any changes to the "FTL Assist Me" mapped key? Or the FTL Modifiers in your Character Set?

If not, then here's what gets sent to make everyone assist.
Slot 1: Shift+Backspace
Slot 2: Right Shift+Backspace
Slot 3: Ctrl+Backspace
Slot 4: Alt+Backspace
If you changed the Key Combination used by "FTL Assist Me", you would replace the "Backspace" in each slot above with your new Key Combination. So if you changed it to F10 for example, it's Shift+F10, Ctrl+F10 etc.

If the ones that use Shift work 100%, and the ones that use Ctrl and Alt do not, then it sounds to me like you have Key Bindings in WoW (or Key Combinations in WoW Macro Actions from ISBoxer) using Ctrl+Backspace and Alt+Backspace (or e.g. Ctrl+F10 and Alt+F10)