Disklavier

Hello!

We have built a new church and purchased and e3 series Disklavier grand piano. I am having difficulty configuring all the features and need some help/advice ensuring I correctly connecting my components. Here is my setup:

Yamaha Grand Piano with Disklavier E3
Allen Organ Model L-10
New iMac desktop

I have connected the iMac to the piano's USB host port via a standard USB cable. The piano is also connected via Ethernet to my LAN which has internet access. The piano MIDI Out is connected to the organ's MIDI In. I can get the organ to play when I play the piano which is a great feature, but when I playback a recorded song, my organ does not play?

I am having difficulty understanding how the iMac can interface with the disklavier - can I play MIDI songs on the iMac which will play on the piano? If so, what software do you recommend and are there any specific configuration settings. I can see the piano from my iMac because when I send a note, the note on the piano plays. The iMac will be located upstairs in my sound booth, so I am looking to have total control of the piano from up here if possible?

Any advice or suggestions as to how to best configure my new church will be greatly appreciated. I don't want to miss out on any cool features! Thanks in advance for your time and help.