For great artist, only fix I can think of (without the DLL or an LUA event telling when the culture bomb is activated) is to remove the culture bomb ability and give that unit a spreading and/or converting culture ability.
btw you'll also have to change
to
for what you want.
btw you'll also have to change
Code:
ALLOW_CIV4_SPREADING = false
Code:
ALLOW_CIV4_SPREADING = true