5.1 surround with sda’s

I’m try to get the best of both worlds. I’ve got a pair of SDA 1c’s up front with an Adcom 5802 driving them and a pair of SDA-CRS in the back (not in the rear) with an Adcom 545 driving them. I also have another 545 that can drive a couple 5 Jrs for the front. I have a great forte 40 pre in the mix and my question was what magical 5.1 device that has a surround chip and some sort of switching so I can do 2 channel and surround?

Thanks smart forum people,

I like to listen, tinker, listen and repeat.