'11 AC how to disconnect rear speakers?

So I wanted better sound and am going to upgrade piece by piece. Anyway got new 6.5"s/brackets/wiring for the front and want to fade everything to the front since the rear stocks reeeeally suck. I don't mind the stock sub though, and when I fade everything to the front, that cuts out the sub too. How can I disconnect just the rear speakers from the head unit without shorting anything so I don't have to fade? BTW I do plan on getting a new HU but that is going to cost some cash (HU+sat receiver+amp+wiring+sat connection to stock stereo+dash not looking stock anymore=bleh). Thanks and sorry if this is redundant, couln't find anything while searching.

 

Yeah hope that plug is easy to find, but if it's a plug than trial and error shouldn't be too hard.

 

So apparently the wiring harness that disconnects the rear speakers also disconnects the sub. I don't know which wire(s) to cut dammit! My new front speakers sound great but I get such bad crackling from the rears.