If it's a workgroup, I don't think you can use AD for other desktops. With SSRS you can get around it by having a user with the same username and password, however, can a SSMS I'm pretty confident in saying it uses the SID of the user, which'll be different on the 2 PC's (even if they have the same username and password).

You'll likely need to use SQL Authentication to connect from other environments other than the Host Machine. (Of course, I'm happy for someone to prove me wrong).