We have an issue where emails with the same subject heading but between different individuals are being grouped into the same ticket and consequently our customers are receiving replies to emails they were not a part of originally.
So for example, one customer emails our support email address copying in another customer they are discussing with - this creates one ticket. This first customer then emails us copying in a different customer they are discussing separately with, but with the same subject heading, and this email is added as an update to the existing ticket, sending the response to the customer in the first chain when this should actually be a separate ticket chain.
How does Zendesk group emails into tickets? By subject heading, and by sender?
Is there a way for us to stop this happening as it confuses our customers and lets customers see replies to an email chain they should not be a part of.
Many thanks for your help,