Heatit Z-Water and Z-Temp2 in association groups

Dear Colleagues,
I’m trying to setup the Heatit Z-Temp2 to control the relays of the Z-water, on Vera Secure, using association groups. For example to control the 2nd relay (Endpoint 2) on Z-water.
Can someone give me a suggestion how to do the groups? I have tried millions of ways, the issue is that I’m not able to set it up correctly, always getting some errors (purging associations error, or loading secure classes error, etc). Somebody succeeded to do it?

Thank you,