Let us build spawners

By "spawner" I don't mean the hidden spots where enemies can spawn, I mean the active body piles (draugr) bone pile (skeletons) and Greydwarf Nests (greydorfs).

They're amazingly useful for the ingredients and materials they spawn, and it's a frustration in multiplayer games for another (normalyl less experienced) player to destroy a spawner because "evil thing bad, must kill".
Give us another use for withered bones, for elder seeds, etc.
Worried about it being too strong? Add restrictions by biome, or make them only function if they're not near another or whatever else you think is fair, but I want me a combat arena :/

Edit: Y'all have gotten stuck on the "if other players destroy a spawner = bad" point.
Yes, it sucks and it has happened, but the main thing for me is there's this entire cool mechanic in the game we can't make use of other than finding in the wild.

Lemme explain my logic. If I find a spawner in the wild I can dig a pit under it, raise dirt around it to protect it, light a fire or put wolf-towers near it to farm the ingredients, or just jump into it and slay a bunch of enemies.
All I'm asking is some more control over where that can happen, as part of the games mechanics. Let us build our own combat arenas, let us utilise them in complex base defence, etc.