Hi Amit
Unfortunately, the order combination functionality is only available on DIMP and there is no similar functionality on the standard ERP.
You can create your own development to confirm orders together using BAPIs BAPI_PRODORDCONF_GET_TT_PROP and BAPI_PRODORDCONF_CREATE_TT to post the confirmation for several orders at the same time. Anyway, it would be a custom development and you need to discuss it with your ABAP consultant.
BR
Caetano