In ERP_UTILITIES_UMC how to fetch payment data against CA number and not BP number

Hello Gurus,

In case of ISU-only scenario we can have multiple CA (Contract accounts) for one BP (Business Partner) in system.

Cardinality: 1 BP to multiple CA.

Currently,I am able to fetch payment data against BP number

But End user Login via CA number.

How can we get data against CA number and not against BP number.

Note: I have standard OData service 'ERP_UTILITIES_UMC' up and running.

Suggestions and comments are appreciated.

Thanks

-Pavan G