Multiple parties in same game

Is it possible to run two separate groups in the same game?  I know I can make a duplicate of a game, but then I would have to update both.  I have started  dungeon crawl game, and may consider running a second group at some time, but if I launch game, I think it lets every player also launch and see the game, even if I want them in two different parties.

1st a clarification: You (the GM and/or game creator) launching the game has no bearing on the players being able to launch the game. Every player registered to your game has the ability to launch it at any time, although they can only see the things that they have access to and the map is whatever map the banner is set to. You can run two groups in the same game at different times, but cannot run two groups in the same game at the same time. There is only one Player banner to show the current map, there is only one Chat window to show rolls and other outputs.

So other than telling players in group A to stay out during a certain time period, and vice versa, I could end up with a mix of the two parties at any time.

Yup, there are even plenty of examples of this: Especially if you look at the pickup-games, you find that some of them have 100+ players. Clearly they are not all there at once, but take turns playing the game. ...I proudly had 186 players for my "Death Quest" last year ;) A small caveat All players can read the chat from the other players, you can clear the chat log but it still shows on the chat-log page. Sometimes player can deduce information form the chat, like what type of monsters the others have encountered or even some of its stats (it shows with the monster hit rolls etc). It sometimes makes the secrecy of the game a bit trickier.

Also, you may want to show a handout to all players and now you'd have to only show it to player a, b and c... Not that big of a deal but it would cause a slow down.  I personally hate when DM's do this.  I think of it as this is our game, I don't wan't strangers coming in here and reading our chat or looking at our characters.

For game play it might be quicker to show handouts to Everyone while playing, and then edit the handout after the game so that only the proper players can read it. ...unless you have a huge amount of handouts, that shouldn't take more than a few seconds after each game.

Another answer would be to make the party token separate for each group.  Name them party A and Party B attach them to a character sheet and give the players in party A permission to edit party A and the same with B.  Then you can just show to party A and they'll all see it since they have permisson for that character.