16.0.3: Can't add Guest User Group to Chat Group

[jakobroehrl]

I can use all of my user groups here:

But If I want to add the automatic created (the Guests App does it) Guest User Group, it does not show up here:

But it exists in the user management and I already used it for sharing a calender with my guests:

[nickvergessen]

I guess it's not a real group on the groupmanager or the group is automatically excluded from sharing.
But at least it's nothing Talk does, so please report at the guests app 👍