I've got an idea, but it's still pretty basic at the moment.

Instead of there being just one person directing a long adventure, there will be several people overlooking smaller 'jobs'. While the majority of them would be minor adventures for a single group, there could be important requests that will allow multiple teams to take it on at the same time. The hub for these could be an inn, which will be the Adventurer's Inn. Also, since I'm not very familiar with D&D's, I was considering thinking up a new system for this.

Any questions, comments, suggestions?