If you are using IS Boxer...

On my melee team, I have two mapped keys for IWT.
One of the keys has a hotkey, and is sent to all windows.
The other has no hotkey, and is sent to only toons in my melee group (action target group).

I have built IWT into some of my DPS keys.
DPS 1, DPS 2 and DPS 3, will in addition to the assist and press of the key, also send IWT.
You could build these as two clicks, or as on key down and key up.
The IWT they send, is the mapped key with no hotkey, which only goes to melee toons.

Then I have another mapped key.
With two steps.
Step 1, enables the (no hotkey) IWT.
Step 2, disables the (no hotkey) IWT.

So when it is enabled, the spam dps click sequences also have me spam the IWT.
But I can turn that behavior off.
And on or off, I retain IWT (with a hotkey), for quest npc's or flight masters etc.