Is it possible for members in the same Steam Group to add each other into party without needing to be in each other's friend list??

For instance, Player A & Player B are both online as indicated by the Steam Group. But they're not in each other friend list, how do they party up together?

yes they an party up

Mind describing how?

go dota 2, at friends option, choose add a friend, insert ur friend number id, from there, there is 2 option, 1. add as friend 2.invite/add to party

So I need to have a page that lists down every member of the group's Friend ID?

Are the any other more straight forward method like the old guild system? Or a right click & add to party feature for strangers like in those Local Area Chat Channels.