I am currently running Savage Worlds for my gaming group. For some time we have been wanting to do a campaign with a noir/Sin City crime drama sort of feel. I was wanting some suggestions on the best way to have players do missions at the same time in different locations in a city type environment. It seems to me that the group wants to be mostly loners and might be more prone to wanting to do their own thing then work together as group... I may be able to go the mob route. What suggestions do you have?
I have been fortunate/unfortunate (you choose) to GM a number of groups with a liking for splitting into multiple parties, and from this experience I have come to the conclusion that you don't actually have to do anything particularly special most of the time.
The key is to switch back and forwards between the different groups very regularly, making sure that everyone stays engaged in what is going on. It is really helpful if the activities of the separate groups impact on each other, as this means that even those not currently engaged by you have a stake in what is going on. You can also try to leave the group you have switched away from on a cliff hanger.
The only time this doesn't work so well is if some but not all of the groups end up in combat. The different timescales of combat make it virtually impossible to run alongside a non-combat situation in the same way. However, even when this happens there are ways of including players not directly involved.
You can give them control of NPCs Extras and possibly Wild Cards (although there has to be an element of trust that they will be responsible with them). You can also give them control of 'the enemy'. I have found that this works extremely well - there's nothing like a bit of competition as half the table try to murder the other half with flesh-eating zombies.
The key thing I've taken away from this is that it gets much, much easier with practice. I now regularly have situations where the party splits into 2 or 3 groups, and am able to handle it confidently. I've even had feedback from players that the game doesn't feel any different to usual when this happens, so I must be doing something right :o)
One simple thing you can do is make extensive use of the Dramatic Interludes found in Savage Worlds Deluxe (or as a free download from Pinnacle's website if you are still using the 2007 Explorer's Edition). If they just want to go out on their own to meet a contact, investigate a crime scene, or do some other story task that will take a relatively short amount of gameplay, you can do it that way. You can either have the player narrate everything like a traditional Dramatic Interlude or roleplay it out and have the card suit determine how it turns out (if you're doing that method, perhaps have it drawn halfway through the encounter).
Even if you don't use the card mechanics from the Dramatic Interludes and just use die rolls (or no rolls), the structure of a Dramatic Interlude would work well for characters doing side missions without derailing the whole game.
Regardless of how you do it, I recommend having no more than 10 minutes for such as side story for one player. Go with it and then switch back to the rest of the group. Or switch between them often enough that no player is left sitting around for more than 10 minutes. Personally, I disagree with other answer; playing Munchkin for half an hour in the other room is not what I want to do with my roleplaying game time. For this reason, I think it's also important to avoid combat during such side missions because although Savage Worlds if "Fast, Furious, Fun", it's much more fun when you're part of the combat and not when you're watching other people fight.
If these side missions are getting exceptionally long, consider having an e-mail or IM exchange directly with the player during the week, especially if your players enjoy writing. That way they can have these side stories without having the other players wait around for them to finish. This method will take a bit more work from you, but if it enhances the story, it may be worth it.
All that said, you should also consider how much you are willing to let the characters diverge from each other. You're going to get burnt out if you run 6 completely independent games that never interact. You may decide, for instance, that you can only handle half an hour of individual side missions and the rest of the time ought to be in a group. If it's getting beyond what you can handle, you should talk to your players about the expectations of the game.
A split party can be a nightmare for a single GM to run in real-time, and the more the players "Scooby Doo" it, the worse it can be.