Problem with Entities and Cover Group

Hello together,

at the moment i am try to build a now Layout to controll the Covers in our House.
For that i have some Covers (for example Office Left and Office right).
Both got the device class: shutter
They work great

Then i tried to get a group for the two covers (Test_group), but this get the icon for Window.

I tried different things to change the icon to match the single cover. But nothing works :frowning:

Perhaps anybody can show me the right direction to go

Nobody an idea?