Relationships within issues

Not sure if this is a nice feature request to have in d.o. but I find it interesting in mantis, a bug tracker I generally use.

While you can relate issues by placing the #ID in the thread, it might be nice to have a field where you can link other issues to a specific one. By doing so, not only you will already know what other issues are related to that one, but this would automatically relate the other issues to the one you are editing.

Right now I sometimes do this by going to one issue, relate it to another one in the thread, then go to the other one and relate it to the previous one.