A small macro question

Hi,
I’ve written a macro that will automatically check one value of a cell and according to it will change a value of another cell.
I ran into a problem when I wanted to move between two files (a master gantt file). Is there a VBA function that enables MS-Project to be able to move from a cell in one file to a cell in another file? or maybe I can hyperlink two activities from two different files?

Thanks,
Assaf.