Custom Purchase order number formatting

It would be helpful to be able to have more flexibility in the PO number formatting. i.e. pull in project data to add to the number. In our case, we'd like the po # format to be <PROJECTNUMBER0001> And the number format for each project would start over at 0001. Examples: 2161230001, 2161230002, etc. Next job 2161240001, 2161240002, etc.