Hi Siva,
You can make two access codes for both the E1 PRIs
as [91T] for the first E1 dial-peer
and [92T] for the second E1 dial-peer
And inform a group of users to use 91 to access outside
And another group to use 92 to access outside
And from cucm,control that the first group cann't dial 92 and the second group to can't dial 91 through partitions
Wish this be helpful
Thanks