From the Inventory Part In Stock window:

1. Populate or query for the parts you want.
2. To transfer the parts to project inventory, select the appropriate lines with parts in standard inventory or project inventory of a different project activity.
3. Right-click and then click Transfer to Project Inventory. The Transfer to Project Inventory dialog box opens with the inventory records that you selected.
4. The Qty to Transfer field will initially show the total quantity of parts on-hand by default. But you can adjust this value to transfer any quantity less than or equal to the total quantity of parts on-hand.
5. In the Transfer To group box, specify details of the project inventory to which you want to transfer the parts. Click on the Program ID field (or on the Project ID field, if your project does not have a program ID).
6. Click List and select the program ID pertaining to the project inventory to which you want to transfer the parts.
7. Similarly, you can continue to narrow down the criteria for the activity you want to select, by clicking on the Project ID, Sub Project ID, and Activity ID fields and then selecting the relevant values from the List of Values.
8. Alternatively, you can enter the activity sequence in the Activity Sequence field, or select it from the List of Values.
9. Optionally, you can enter a note text, or select the Print Barcodes check box if new bar codes are to be created.
10. Click OK to transfer the parts to project inventory.

Hi There 

Does Apps 8 Project MRP have Netting groups? If so this feature could give you a solution to your problem. It allows PMRP to run across several projects with material transfer options. 

Regards

Lee