Today I can setting in workflow condition Assigned to ( and select a user ).
I need select a group ( rather than a single user ).
That already is supported and depends exclusively on the field type. The image you show is probably of a field that does not support groups.
I tried at on line demo, create a new workflow in contact ( called Test )
I tried set iF Create by ( "specific group, like Marketing " ) workflow should be execute, if user in another group, not.
But I don't have a Group for setting, only User.
What I do wrong?