On an attack, the game checks adjacent cells of the same level. If you want a more involved/advanced check, it needs to be coded. That sort of thing is up to dio and sol. And they are making this stuff for free. Donate, do it yourself, or make puppy eyes and try to engage their interest in something.
So...

....Dio?
add new kit? Field guns.
Early game 2x2 units gals can use. High firepower but low mobility (TU = 50?). Big guns that gals may already have access to but reconfigured.
The bandits already have the 25mm.
2x2 wheeled pirate cannon. Alternate to the hand held cannon but much higher fire rate and reload.
Volley gun. 4x pirate cannon with 1 or 4 shot option.
Same idea with MGs, grenade launchers, rockets, and mortars.