HT/2 channel setup sharing is hurting my brain

I used to know this stuff.......but this one is driving me a little insane so any help is GREATLY appreciated.

This all started with a very simple and inexpensive HT setup with a Denon AV receiver, in-wall speakers and a sub.  Then I came to my old Audiophile senses and realized I needed a 2 channel set up so I bought a pair of Klipsch Heresy II's, a Muzishare X7 integrated tube setup and a SVS SB-2000 sub!

When waiting for the integrated unit I hooked up the Heresy to my HT setup and fell in love with how they sounded on it.  I then added the SVS sub and a Y connecter to run the two subs on the HT setup and fell more in love.

NOW.......how to integrate it all together????  They will never be used at the same time since they are in the same room.  I think what I'll end up doing is just upgrading my in-wall speakers in the future and have a dedicated 2 channel setup in the same room but having a tough time with the subs right now.

Would really like to use the SVS sub for both the 2 channel and HT but can't figure out a way to do that in my head.  The inexpensive Amazon 12" ported sub has speaker terminals for in and out so I could wire my Heresy through that sub, it's not the most musical of subs but it would work.  If I do that then the LFE input is available, so could I have my AV receiver hooked up to the LFE when watching movies and it still work even if the 2 channel speakers are wired thru the in and out terminals?  Again the 2 channel speakers or setup wouldn't be on at the time the HT would be going.

The integrated tube amp does have a pre-out section, not sure if that helps in this scenario but I thought I would throw it out there. The SVS only has a line level RCA in and out.

Hope this still makes sense.......... ;)