Components creation for RMM

I have a system with three subsystems A, B, C. I have created components in DNG and ETM but stuck at EWM. I created stream in SCM and add three components A, B, C in the stream. I understand that these components can be baselined to get snapshot at stream level in SCM. What I do not understand is how to create streams/components for RMM. RMM shows the same stream and components created in SCM. Let's say  all three subsystems A, B, C have code developed and coming from visual studio and models coming from Rhapsody; how can I segregate code/model in EWM?