[otrs] locked ticket

Hello, i am new to OTRS. I have freshly installed OTRS system with users and all is running perfectly, but i have one question. I need following thing: users must see other users locked tickets. For example: If John wants to see all locked tickets by Sara, he for example press some buttons or something like this. But case of Search->User name there will be displayed all tickets which this user had and have now - is not acceptable for me. Please give me some solutions. With best Regards, Viktorija