Setting up Nait 5i and Nait XS together

Hello. I have a Nait XS set up with Harbeth Super HL5 speakers in my primary listening room, and am very pleased with it. I would like to power speakers in a nearby room with the Nait5i, but since there isn't a simple "tape out" on the Nait XS  I'm not sure how to do that.

First post--appreciate the chat, and any help with this-

JMH