Search form only display countries with properties instead of all countries

Hi,

In search form a country dropdown shows all available countries which is very user unfriendly and also misleading. Is it possible to limit the dropdown filters to only ones that are available? So for example if the only properties for sale are in Canada and US only those two would be displayed? The same applies to other filters, like town, type etc. All of them should only show available options and not all of them.

Thanks,
Grega