Open only a single ticket for follow-ups to a closed ticket

[rblst]

Hello,

I have set up my queues to open a new ticket when a follow-up arrives to an already closed ticket.
My problem is that a new ticket is created every time a follow-up to this closed ticket is received.
How can I set up OTRS so that only a single new ticket is created in this case, and follow-ups are added to that ticket?

Regards,

rblst