[otrs] Change ticket state to open if another ticket is merged to it

Hi, I am looking for a way to let the state automatically change to open of the ticket that you merge another ticket into. The reason is that often customers do not care about the ticket number in the subject and open a new ticket and when merged to the "main" ticket it disappears because the "main" ticket is still in pending or close state. Is there a way to achieve this? Thanks!