How to set a row level filter for a group?

[ArcticPuffin]

Hei,
is it possible to add row-level authorisation for groups?
According to the documentation, I tried this:

        {
            "group": "my_group",
	    "schema": "some_schema",
            "table": "table_one",
            "privileges": ["SELECT"],
			"filter": "col1='random'"
        }

but get an Access Denied SQL Error.
I can replace the group by a user with no problems:

        {
            "user": "my_username",
	    "schema": "some_schema",
            "table": "table_one",
            "privileges": ["SELECT"],
			"filter": "col1='random'"
        }

Can anyone help here or does anyone has some experience on row-level authorisation for groups?
Thanks and best,
Sven