There should be a 'depends on...' status for issues

At some point during the history of an issue, there might be cases where another issue needs to be fixed first in order to move on. Usually these issues are set to 'postponed' or remain 'open'.

I propose to define a new state and have it available in the issue status selection drop-down menu. A 'depends on...' status. Once selected, an extra field should become available for inputting other issue number(s). I've seen this in the mozilla.org bugzilla bug tracking system. This allows having a 'Depends on:' information field in the issues' summaries that links to issues that need to be addressed before the current issue. Also there is a 'Is required by:' info field that links to other issues that depend on the current. What I mean to say is that this is a two-way relationship between depended issues.

Thoughts?