Search on Requisitions using major category "KFF"

Dears,

Have a good day.

Please your help for the following:

Our Oracle version is 12.2.12

Using the responsibility "Purchasing Super User" —> Then Buyer Work Center function —> Then Requisitions function: The system here allows us to search for all un-assigned requisitions using KFF category and our KFF category consists of tow segments: Major and Minor. The system forces us to enter the values "Major & Minor" if we need to search for un-assigned requisitions using a specific category.

We need to search using the major category only, How can I achieve this?

Thank you.