Mod to start a new "related thread"??

[apokphp]

I don't know if there is anything that exists currently to do this, but I think it would be a useful feature/mod.

I run a debate community. Often times our discussions spawn sub-discussions that really should be left for another thread (else the current thread would be taken off-topic or misdirected).

So to resolve that, we ask that people start a new thread and simply reference the old thread that started the new discussion (after all, sometimes it's important to have the "backstory" or a few key points that have already been mentioned).

So the member starts a new thread, sometimes quotes from the OTHER thread and provides a link to the OTHER thread.

So...what about a mod that creates that new thread automatically? Perhaps a new button (next to Reply) that will...
Create a new thread

1. Auto-reference (via link) the old thread from which the new button was clicked
2. Possibly include a prefix for the new thread's title indicating that this is a "spin-off" discussion from an existing, older thread.

Does something like this exist? If not, can someone create this? How difficult would it be? I'm not an expert PHP coder, but in theory, it seems fairly easy to do, no?