I don't believe this is an ONLY situation.... if you go to the User list right now, try leaving the USERNAME blank, and sort on any one of the three options, see how it shows things. It can be quite useful, but just now, sorting on date of registration isn't always too useful for most of us. May be for the Admins though.
So, if there's a Country option, and you sort by Country, you can go to the USA section and yes, due to population numbers you'll get too many peeps in a crazy order. But if you sort by Country, you can go to the UK section, and there may be 100 (?) people... and if you sort by Suffolk (which if you are from Suffolk in England, you'll know that it makes sense), you may have only 10 or 20 people!!
BUT, if you sort on State or Region whatever it's named, (leaving the others blank or unspecified) it will bring up everything in chunks based on that field. and you can pull them out that way.
It may well be possible for the forum search engine to be set so if someone sorts based on 'state' or geo region or whatever it gets called, it can then be set to also do the next block as a secondary choice (C, N, NE, NW, S, SE, SW, etc) . I'd really have to see the forum options to say.
I don't think it's an actual programmer that's needed, it's usually an option available in the 'set up'. These people usually allow lots of options for sorting forum membership.