Unload objects placed on map far from player

so lets say i have my level full of stuff (which makes it kinda slow) but the character gets away isnt there a way to unload it or something and if the player goes near it loads it kinda like what open maps use they just load stuff at certain distance and is there a way to make it relative like for multiplayer that each player loads their own part of the map and when they meet with other player the objects (movable) are at the same position for both players