Differentiate between two otrs systems

[aph]

We have a problem that we and one of our partners use OTRS with same system ID and thus similar ticket numbers. Since we exchange information between the two systems, it can be problematic. Is there a way to differentiate between the tickets in two systems, where we don't have to change our system IDs?

[aph]

Update: If I change the hook, all the tickets now get hook changed in the ticket number, which is not a big issue. However, when the customer sends a reply to existing ticket with the old ticket hook, a new ticket is opened although the ticket number hasn't changed (and the customer reply contains the ticket number). Is there a way that when customers reply to the email with old hook, it is correctly placed under the ticket with the corresponding number (which now has a new hook)?

Note: I tested whether incoming mails are assigned to the correct ticket number as described under https://github.com/OTRS/otrs/blob/rel-3 ... irst-email

[crythias]

viewtopic.php?f=60&t=22681 might be of interest (?).