Custom Task Field & Custom Project field linkage

I have a custom Project pick list "Project Health" calculated Field based on other custom Project fields RAG for Schedule, Budget, Resource, and Scope.

Current Formula:

If($C_ProjectBudgetPH2 = "Red", "Red", 
If($C_ProjectResourcesPH2 = "Red", "Red", 
If($C_ProjectScopePH2 = "Red", "Red", 
If($C_ProjectSchedulePH2 = "Red", "Red", 
If($C_ProjectBudgetPH2 = "Amber", "Amber", 
If($C_ProjectSchedulePH2 = "Amber", "Amber", "Green"))))))

The above works great!

What I need to do is:

I have created a custom Task field that gives a RAG based on the task due date and today if the task is open.

If((DateDiff($C_CurrentDatePH2,$DueDate,"D")>14)&& ($State = "Active"), "Amber", "Green")

I want to use this custom task field in the main Project Health at the top of the post; however, you cannot see the custom Task field when editing the Custom Project field.  All I can find is the Custom Project fields.

Is there any way of linking a custom Task field to a Custom Project field?