I have project schedule A rolled up to a Master Schedule XYZ. I have project schedule B rolled up to the Master Schedule XYZ. Can a link project schedule C to Master Schedule XYZ and to project schedule A at the same time?
You can link from any project A,B or C and indeed a task in the XYZ master if you want to, Simply display the items you want to link and drag a link between them. Once you have done this you can see the anatomy of the link and manually enter other links as you want. Notice that if the second link would be made illegal by the existing link you will not be allowed to set up the second link, for instance if you ended up making a circular relationship.