Allow dependences to be defined in the child plan as well as the parent

When creating dependencies for plans which are dependent on multiple parent plans, you currently have to open each of the parent plans and define the child on the dependencies tab.

Once the dependencies are defined, you can view the parents from the child (from the dependencies tab, expand the Advanced section and they are listed as "Parent Plans")

It would be much easier to be able to define the parent plans from the child, from the one screen, rather than having to open multiple parents.