Territory Management Restriction

Hello Experts,

My Requirement: Access for Creation and Process of Business in user window should be restricted based on the region.

if you are in region A , iam in region B , i should not Create any business transactions to the customer who are there in your region ie A

How can i do it..?

Currently i have territory management with employee list assigned to respective territory,

system can validate at BP Level ie Territory assigned to BP should satisfy the employee territory to which he is assigned to.

can any one still explore on it?

Thanks in advance

chinna babu jollammagari