You can use a proximity search in the estate search and in the interest form.
Add the field
In estate lists, add the field “Geo Position” from the category “Geo Range Search” to the field list. Expand it using the arrow and activate “Filterable” so that it will show up in the estate search.
For interest forms, the field is in the category “Search Criteria”. Simply add it to the field list.
There will be a new box called “Geo Fields” above the field list. You can configure the proximity search to your liking there.