Yeah it would be nice to institute something like that, but there would definitely hangups in the implementation. For example, there exist many organizations where the only thing needed for active membership is a monthly fee. Just like in Australia, there are many remote areas of the US where the nearest neighbor may be 40 miles away. There are always problems with restricting the ability of any citizen to own guns, and a mandate to interact with others would probably not go over well. It'd definitely be worth looking into on a state level, I think. It would probably be best as a community initiative, though.