As far as I know Robert, Tennisopolis doesn't allow you to send player request by bulk emails. I believe you have to be accepted as a friend, then you can send them email. I'll ask Mark Mayor, the site owner about it.
Robert, good question. Go ahead and put in "San Diego 4.0" in the search option at the top left. I tried it and got a lot of profiles. You will have to look through these profiles a little bit. The other option is to find a group, so click on the Meetup tab and pick San Diego as your region. You will also see posts there too. Good luck!