ATV3 & Multi-Zone Home Theatre System

I replaced my ATV3 with a 4 for our media room and want to hook up the 3 to our living room home theatre setup. The problem is, we have three zones with the living room setup, two indoor and one patio for music. The TV is a recent LG smart TV.

Currently, it’s set up with HDMI from the cable box to Receiver 1, RCA cables to Receiver 2 and HDMI from Receiver 1 to the TV for video. With both receivers on we can listen to Pandora and cable music through all zones simultaneously which is the goal.

But with the ATV3, attempting to play music from iTunes, I can’t get sound in all three zones plus video for the ATV3. I’ve tried a number of combinations of HDMI and optical cables including a splitter for the optical cables but I can’t get it all working together. Both receivers have multiple HDMI ports and an optical.

Appreciate any help.