This is probably a really stupid question.... but, I've just bought a second Sony UWP radio lapel mic to use on my Sony Z7.

The factory default channel is the same as on the original mic, so I got a lot of interference/distortion.

I've tried to follow the instructions on setting up the second mic frequency, but I'm confused as to whether it should be in the same group or a different one, or the same group and different frequency

Any advice would be appreciated.