Mechanism to Encourage more Regional Conversation?

I'm wondering if it'd be possible to create a mechanism where one could post a thread to a regional forum and choose not to have it show up on 'latest forum posts' on the homepage? My rationale for this is that there are certain conversations that are best had by folks who live in that region. This would reduce the incidence of someone who doesn't have a stake in the conversation (or at least less of one) say from Florida commenting on a post about a random local issue in Montana that they don't really understand.

Obviously good contributions can be made from afar, but I would contend that they typically aren't. This way people who are actually invested in a region enough to click on that specific forum and see what's new are more likely to contribute and those of us that are just bored at work/school/etc and trawling the 'latest posts' will be less likely to clutter other people's conversations with our (possibly less insightful) opinions. Again, this would be optional and up to the original poster's choice/discretion.

An example of this is that I would love to get a read on the Smith Rock climbing community's consensus on a given issue, (or at least those who read MP forums) but don't want to use a forum post to solicit for those opinions because everyone and their brother will weigh in on it. I feel like this could provide a good middle ground between some sort of 'locals only' forum and