I was able to do this entirely within hass, no OZWCP needed on version .49.
- Under “Z-Wave” > “Z-Wave Node Management”, select the node that will be sending the command from the drop-down.
- Under “Node group associations”, select the receiving node under “node to control”
- Then select a group (“group 1” works for me).
- Finally, click on “add to group” and it should make the association.