Hi,
User CL_BCS to send multiple mail id's.
Also Refer below similar thread for more details.
http://scn.sap.com/thread/1731311
How to add cc recipient using cl_bcshttp://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/e009f97e-ee5d-2e10-31ba-9c9509e5925c?overridelayout=true
Regards,
Sujeet Mishra