The actual name "Team 7" was created when Martin, Lee and I were explaining this concept to a friend of ours. She had an objection to what we were telling her and she wanted to prove her point with a hypothetical situation. I don't remember what that was because she started out her hypothetical situation with the phrase, "OK, for example, you three boys are all sevens..." We all laughed very hard at that because we all know that we are sevens but you don't tell someone that they are a seven. It's like calling someone who is obviously stupid a "dummy". So after that we called ourselves Team 7. Of course we didn't let Nathan into team 7 because he is clearly a 9. :) Of the original Team 7 I am the only one not married. I guess I am just not persistent enough.
Look for this in your single friends or friends who are getting married. You will find examples of team 7 everywhere.