Can I integrate 5Ch Surround with my Stereo setup?

Hi Folks:
I currently have what I think is a high-end stereo set up, with CRT (Electrohome 8500HT) and HTPC on the way. My question is, can I somehow integrate a full five or seven channnel surround set up with my existing stereo, leaving my stereo signal path unaffected when I'm just listening to two channel music? My existing stereo system is Supratek Syrah preamp, Blue Circle BC2 monoblocks, Audio Physic Virgo speakers, Teres 245/OL Silver/Shelter 501MK2 vinyl rig.

Ideally, I'd like to be able to introduce a three channel power amp to the system somehow (like a Bryston 3bst), using that for rear and center, and still use my BC2s to drive the front channels, also introducing a preamp/processor to drive the sound for movies, but not have to plug anything out when I switch from movies to listening to stereo (still want to rely on my supratek syrah as preamp for music but can use something else for movies). Am I asking too much? How do you guys integrate stereo with movies, without having to rely on HT preamp/process for music? Thanks for any and all input!!!