How to default source of supply in PR generated from PM order and having MPN associated?

Hell All,

we are planning to have MPN and wanted to default source of supply for PR's generated from PM order.

For Non stock item (also MPN is created) user will put requirement in PM order against Material and on release system generates PR, Now PR generated is not having source of supply and user need to click on button source of supply in PR change mode, can we default or automate determination process?

if yes how?

Thanks

Sunil