When you're a member of a Group in Player.me, the banner at the top contains similar buttons a Player.me user's profile page.

This view is as a member of a sample group in the site.

If you leave a group but decide that you'd like to come back, you'll have to send a join request again:

This is similar to adding other users in Player.me.

The owner of the group will receive a notification for your request.

They will have to accept it, of course.

After you have rejoined the group, you can browse the group in the Player.me site as before.

Things are slightly different if you're the owner of a group and you leave it. You can't exactly accept your own request to rejoin the group, since you were the one with permissions to accept that.

Notice the difference in the buttons that show up.

Logout of Player.me, then login using the group's name as the username -- with your own personal profile's password.

This workaround is made exactly for situations like this.

You'll notice that you can now see and accept the request you sent from your own profile.

You can also invite your profile back in.

When you return to your own profile, you'll see the group there as before.

Including the option to login as the group from your profile.