Automatically updates in Requirements in separate Project which has associations with each other

Hi

I have Main Project with almost 1000 requirements and have separate one (Project EC - 30 requirements). I did association with both, but is it possible to get automatically updates/changes... whenever I will do the change in requirements of Main Project then I will get those changes in requirements of Project EC? and other way ?

I did that kind of separations in order to give access to external group of people, who doesn't need to see what else we are doing

Regards

Aleksandra