Hi,
Why you want to have default Schema Group of Vendor in Vendor Master Creation?
You need to enter Schema Group of Vendor manually during vendor master creation process(Xk01 / MK01)
Imagine if you have Multiple Schema Group of Vendors for same Purchasing Organization where you have Multiple MM Pricing Procedures with Multiple Schema Group of Vendors ,then how and which Schema Group of Vendor - you needed as defaulted in vendor master creation process!
Regards,
Biju K