Hi Kiran,
there are multiple ways of achieving it
either you can use only one transaction type like ZMIN for all different sold to party OR
ZMIN & YMIN both for 2 different comp requirements like I have said before using multiple transaction type...check the SPRO documentation for this and decide what is best suited for your cased based upon the exact Functional requirements
further you can create different sold to party for each comp....and then support for each sold to party or company
use BRF+ to determine support team determination
with security you can restrict the message based upon IBASE or Support Team(Partner) etc.
http://wiki.scn.sap.com/wiki/display/SMAUTH/Use+Case+Overview
Let us know if you need more help with this.
Thanks
Prakhar