I copied the FTL DPS Keybind section in ISboxer and pasted and renamed Melee.

Under the first 3 DPS keys 1-3 i added a second step to interact with Target.
Then put my Melee toons under that Melee Keybindings.

This way when i use a mixed team i dont have casters trying to interact with target and interrupting their casting.

If you do decide to do this. Just make sure you add this new key binding set to your General Keymaps on and off hotkey.