Determine supplying plant in PO STO

Dear Guru,

Currently, we are running inter company process using PO-STO. However, only one default supplying plant can be determined from vendor master (according to standard function). Anyway, we have new requirement to pick up stock from supplying plant other than defaulted in vendor master. Is there any way to do customization so that multiple supplying plant could be determined when creating PO-ST? Thanks for your advice.

BR,