[Lizard]

lpj -- I think there may be a bit of a misunderstanding here. You can create multiple projects, save each as a separate file, and open each in a separate window at the same time. The only real limit there is your computer's memory.

On the other hand, OmniPlan cannot yet share resources across projects. If you must have a separate file for each project and a person is working on two projects, you should set their available units in each project to 50% (or the appropriate balance) so that they aren't assigned a full work load in each project. The other approach would be to delete their work hours from the calendar in one project when they're scheduled to work on tasks for the other project.