Can I create my own community?

Unfortunately, you can't create your own community. 

However, you can curate your own friend list. Just switch to "Your friends" at the top of the leaderboard.  If your friends are already using HOLD, add them via the round blue button with the "+" on it on the top right. If they aren't using HOLD yet, invite them via the square blue button "Invite" in the scoreboard. It'll get you an additional 50 points when they accept the invitation.