How to restrict the list of values in Style under Create Agreement page

Summary:

There is a client requirement to view only the 'Blanket Purchase Agreement' in the style list of values under create agreement page. I am trying with creating custom roles using the seeded Procurement Manager role.

However unable to achieve the requirement. Is there anyway apart from Role customization to meet this requirement like page customization?

Content (required):

There is a client requirement to view only the 'Blanket Purchase Agreement' in the style list of values under create agreement page. I am trying with creating custom roles using the seeded Procurement Manager role.

However unable to achieve the requirement. Is there anyway apart from Role customization to meet this requirement like page customization?