Rerouting channels on a reciever

[giderac]

Hey can someone tell me if this feasible and if its really worth doing? I'm trying to use some old speakers from the 80's to connect to a new hdmi receiver i will be buying in the near future. Right now i have 4 speakers, a pair of ads l420, and a pair of RCA type 502s1 loudspeakers wired to a small tweeter in a passive setup each fitted in their own respective custom box (these might be really old maybe 50's or 60's but from what i remember they sounded pretty good and got pretty loud). I'm trying to spend the least amount of money possible and still have a nice surround sound setup. Can i get away with just buying a center channel, a receiver, and using my 4 speakers for a nice setup? Is there anyway to reroute the sub channel to those rca loudspeakers? Any help would be greatly appreciated.