In a few months I'm going to be taking control of a group and running through a campaign of my own creation. The campaign we're running right now only has 3 PCs and the DM, so a fairly small group. However, we have a lot of people interested, and some old players returning for my campaign. This will bring the player count up to a whopping 9 players. Also, for the majority of the campaign the group will have at least 1 NPC companion that will be as powerful, if not moreso than the party (for story reasons)
I've never played in groups this large, and I'm expecting that there will be a few problems with this. Combat is a fairly large portion of this campaign and in addition to a very cluttered board, I can't think of how I can possibly balance combat for 10 players. My solo encounters have been modified enough that I think they will work, I still don't know how I should run the more common encounters.
As it stands I am considering splitting the party up for the majority of the campaign. I have a very diverse group of players so I'm thinking that while some are out on a combat mission, some of the others will be in town solving problems there, maybe helping the police solve a crime or shutting down a local gang.
I just want to know if this plan is viable and any alternatives that you have. Also any other advice on running large groups would be appreciated.