change vendor for a condition type

Dear friends,

i have a requirement where i have a large number of conditions to be maintained for a vendor other than the principal vendor in the PO. if i have to change the vendor for each condition in the conditions tab it takes a lot of time to create a PO and defeats the basic purpose for having SAP. is there a possible way to change the vendor in all the conditions at a time using some user exit or any other means.

thanks in advance