Adding matter switched to device groups?

I have lights connected to Onvis S4 matter over thread switches. They show up fine in HA, and I can control them individually.

I also have some hue lights.

I created a group “Living Room Lights” with my Hue lights, but cannot add any of my matter devices to that group.

For instance, I have an entity id of “switch.ne_living_room_corner_lamp_switch_3” but cannot search for or add that entity to the group.

Is there a workaround or should I file a bug against the group integration?