hi,
i found some suggestions but they are old, can you help me to dim only the lights on in a group? I can’t figure out how to do it 
If your lights are in a traditional Group entity, group, then you need a template to identify its members in order to dim them.
If your lights are in a Light Group entity, light, then there’s no need for a template to identify its members in order to dim them.
So are you using a traditional Group or a Light Group? If you chose to use a traditional Group, for dimming lights, why did you not use a Light Group?
In addition, what’s the point of grouping lights if you intend to only control some of the group’s members?