The 7175 has Pre Out/Main Ins, so just get a Y adapter and run the subs off the Pre Outs. Should work fine.
I see you own the Silverline SR 11 and the Tyler Talo mini reference. Can you offer any comment regarding their sonics - I am looking for speakers that can sing at low to moderate listening levels. If they need to be cranked up in order to appreciate their finer attributes - they may not be for me.
Thank you for your commentary -