list the users who are all belongs to the particular transport request?

Hello experts,

i want to know the users who are all belonged to the particular transport request.

i.e., if the USER1 created a new transport request and later USER1 added another user (USER2) for the particular transport request which is he created before.

because i wrote a program to enter the entries in a table and assign the transport request number. if the user gives a transport request nuber which is not owned the current user means it get dumps...

any suggestions please...