Redmine

Context: I have a helpdesk pluggin and may receive dozen of emails in the space of a few minutes from clients advising that our web service is running slow. These emails automatically create issues in Redmine.
Once I resolve the problem I would like to "link" these issues to a master issue.
Instead of updating each ticket individually to relate each one to the master issue.
I would like to select these issues in the "issues list" and add a relation to the master issue.

In my issues list I selected 6 issues (check box on the left),right click and given a menu with "edit" and other options which is great but there's no option for "Related Issue". Is this a bug, a non existing feature or perhaps a configuration that I could do to have this functionality? If I select edit perhaps have an option to add a relation?