Do the steam community links work for you? Because they should lead directly to my account/ the Steam group.
And from there you should be able to add me as friend, and the group should also be able to find there on my profile.
Delta_Force* is the full name of the group, abbreviation DF90's
If the links doesn't work maybe you'll have to search for the groups.
As long as we have the same version of Delta Force it should work. I have the latest version, so we should be able to play via Evolve. I haven't tried it yet.. But if i get some time over today me and a friend will check it out!
I will comeback with more info later today (if evolve works etc.)