@beforewisdom nope. It's on the instance level. The website you're on may allow you to block or hide posts from kbin but I've never used veganism.social so idk if there's an option for that on there.
I have to wonder what the issue is though? Did you have a bad experience? By default all your posts go out to the whole fediverse, kbin included. That's kinda the whole point of federation.