What I would do is:

One mashed button, on whatever hotkey you want to mash.
Have it do a series of Do Mapped Key actions.
Then have a Mapped Key for each toon.

Something like:

Main Mapped Key
- Hotkey "1".
- Do Mapped Key (Toon A), Target: Toon A
- Do Mapped Key (Toon B), Target: Toon B
- Do Mapped Key (Toon C), Target: Toon C

Mapped Key: (Toon A)
Step 1
- Keystroke Action, Send "1" to Toon A
Step 2
- Keystroke Action, Send "2" to Toon A

Mapped Key: (Toon B)
Step 1
- Keystroke Action, Send "3" to Toon B
Step 2
- Keystroke Action, Send "4" to Toon B
Step 3
- Keystroke Action, Send "5" to Toon B

Mapped Key (Toon C)
Step 1
- Keystroke Action, Send "1" to Toon C



Doesn't matter the window you're in.
You press your hotkey.
And it has each of the toons do their own mapped key.

And that mapped key can be as many or as few steps as desired.
You could have their key not advance for 'x' seconds, if you want.
One toon could be one step, mashing a single key.
Another toon could alternate between: 1, 2, 1, 3, 1, 4, 1, 5.... or whatever.