I doubt something like this exists, but if you are capable of scripting, try either
removing all world objects, locating RC & generic prop IPL files and converting to .map or .lua, then fine-tuning from there for any missing or unwanted objects
removing all world objects except for RC & generic props, by grabbing the IDs from IPL's that you want to exclude from the mass world object removal
make a script that deletes objects outside of a zone that you draw on the world map, this zone could perhaps even be created using colShape to detect if an object is within the shape