Modifying templates for HotA.

Where is the rule stated that ore and wood mines should always be within a 15-cell radius of the starting town? Is it in the map template or in the game itself? I have an idea to replace an ore mine with a watchtower in this map. So that it's always nearby. And even if this is hardcoded in the game, perhaps it could be adjusted in the future. So that watchtowers could also be one of these objects. And very important objects (like consulates) should ideally be linked to roads, so that they are always prioritized in this regard.