Sony home theater subwoofers?

[Ellectronics]

I bought 2 Sony SA-W3000 12'' home theater subwoofers. They have an "in" and an "out" they are self-powered. I have a 7.1 sony receiver. My question is... Can I send the signal in 1 subwoofer and then out to the other and it still be the same signal...or am I going to lose signal and then I would need a 7.2 receiver. It is sort of like "piggybacking" on them... Please let me know! Im stumped on this one! Thanks all!