I suppose that a person in charge per project can be registered in your project management system.
Therefore I suppose that it is easy to grasp a person in charge per project.
But if one person is registered in two or more projects at the same time, it is not easy to grasp projects per person.
Does your project management system have some structure eliminating the above troublesomeness?
Can users interrelate data of two or more projects?
Sincerely yours