Hi Harry,
I understood your original question to be how to edit the inserted project
tasks not hide the display of those tasks.
When you create links between tasks in different projects, the external
predecessors and/or successors appear as light gray - so called "ghost"
tasks. If you do not want to display the tasks, choose Tools>Options and on
the view tab, uncheck Show external successors and uncheck Show external
predecessors.
I am not sure I understand why you want to hide the display of the tasks
however. Also, hiding the display does not remove the link relationship. I
assume you linked the tasks across the projects because the schedule of the
tasks in one project drove the schedule of tasks in another project. IMHO, I
would leave the external successors and external predecessors showing.
Hope this helps.
Julie