Channel groups are not in wide use. There are several bindings making use of them. You can try to use XML Schema to find out what you can do with channels. For example addChannel and updateChannel instructions support groupIds tag which may help you to associate channels: openhab-core/bundles/org.openhab.core.thing/schema/update/update-description-1.0.0.xsd at main · openhab/openhab-core · GitHub
