Redmine

My project has a requirement that several individual be notified via email of any change to issues in which they are involved. Individuals would choose the "types of issues" they are interested in. When looking at the functionality Redmine currently has to offer, it appears that what I call a "types of issue" is defined well as an "issue category".

Would it be possible to give users the ability to be notified upon the creation or modification of issues falling under the issue categories they are interested in? There are at least two angles in which this could be approached from a UI standpoint. First, let a user pick the project/category combinations they're interested in from their "My Account" pages. Second, allow administrators to select users to be notified from each issue category's edit page.

Sending the actual email notifications is another story...I don't know how complicated such a thing might be.