I was suggestion a mod like lcpdfr but the opposite side :) but where you can pick a side of a gang and enter a dot and has a room where you can pick a gang model related to that gang and you could raid places disguise as other gangs or police officer so they wont attack only when you attack there guy or see something suspicious  but when you attack the police they just show up as red and wont get cop stars on you and so they cant make it harder on you when your doing a gang raid so you wont be on 5 stars and trying raid a gang for fun and the police wont ruin it they only come for you if you attack them or they see you and they attack you when they see you cause i think that be more fair than cops already getting wanted and just trying have fun and raiding 

There's this mod (http://www.gta4-mods.com/script/turfwars-f17526). Somewhat close to what you are describing. 

I knew that someone was ganna reply that mod link to me but no i didn't like how cop always get you wanted that why i talk about the new cop idea in this post so much

Then you are requesting an programmer,