How do I establish boundaries between coworkers and myself (so we strictly communicate about work-related things)?

Anonymous

I am concerned that if I don't respond to their non-work related conversations, I'll be harassed or not be seen as team player. I care about them as colleagues and will go out of my way to help them with work. How do I politely stop them from engaging me in non-work related way? I have in the past engaged with them when I was lonely and unaware how toxic the workplace was. Now that I have been here for awhile, I have been victim of bullying/gaslighting from several coworkers and manager here. One coworker says that we are work place brothers and seems to get a bit annoyed if I don't agree. Help.

Updates
18 d
To give you an idea of the toxicity:
-Group of coworkers has joked about another coworker behind his back about being an animal that pees everywhere.

How do I establish boundaries between coworkers and myself (so we strictly communicate about work-related things)?
2 Opinion