Call detailed view from 1 CRM system to another CRM system

Hi Experts,

I need your guidance regarding below requirement.

Requirement: Need to display detailed view of a Service request from ICM(Investigative Case Management system) in Incident Management (separate system) when clicked on the Service Request Number assigned to a case(No idea why the user is using 2 CRM systems).

Issue: As per my knowledge we can fetch the data from ICM system using RFC or web services and can pass to the corresponding views but the user wants to display the views of the IM system as there are some extensions (custom database fields and tables) in the IM system which are not available in the ICM system.

Please help me how to achieve above functionality.

Thanks in Advance,

Manasa veena P.