Hello Arun
You can map this requirement using a quota arrangement.
You can define that one of the quota items will be produced internally with a production version and you define your capacity as the maximum released quantity for this item.
The other item will be defined as subcontracting.
Take a look on the following note which provides instructions to set up a quota arrangement:
http://service.sap.com/sap/support/notes/1508647
BR
Caetano