Hi Jatinder,
1. Are you trying to say, you have multiple customers registered to the same Call manager making outbound calls using the same 3825 gateway where each company has 2 BRI lines of their own and use only these two lines to call out?
2. Can you let us know what kind of gateway are you using?
3. Can you help us understand the current CSS/partition setup?
4. When you say you are not able to dial the use of another company, are you trying to say you are unable to dial the internal extension of another company which is registered to the same CUCM?
5. What is the partition you have assigned to the directory numbers of both the calling and the called company users?
6. If using same CUCM for different companies, do you have different route patterns for users of different companies?
Aseem