Multiple Credit Segments under Main Segment

Hi Experts,

Current Structure:

1 CoCd

1 Credit Control Area

1 Sales Area (having 5 different Material Groups)

1 Credit Limit of BP (shared by 5 different businesses of each Material Group)

Now the client wants to create 5 Credit Segments, 1 for each business (material group) so that every business has it's own credit limit.

Can anyone tell me how to credit multiple credit segments and assign it to one Main Segment.

Also would like to know if it involves any enhancements or its just configuration.