Mange Family Table in Windchill ?

In Windchill , we have mapped part_name & part_number as an attribute .

File name : Cad Name

Number     : part_number

Name         : part_name

So that, the attribute will be updated in Windchill based on the value assigned in the parameter list inside the care (Tools-Parameter).

In family table Generic & Instance, we have assigned the value for part_name & part_number (Ex: Part_name: Plate,  part_number: 12345).

The value remains same for Generic & Instance.

Since, the parameter  part_number: 12345 is same for generic & Instance (Note: enabled WT Parts), not allowing to upload.

It is showing error like"CAD part is not unique".

And we can't assign different part_number for generic & Instance as per our standard.

So, I want to know the best way to handle the family table part like above mentioned scenario