Your entire time with the company, be polite and cordial, don't say risky things, basically be a good boy. But importantly, stay social. Just politely social.

After several months of this, enough time that your fellow employees and management are well aware of your personality, go to the PM in private. Threaten them that if they don't leave you alone you're going to break into their house at night, sedate them, dislocate their jaw and take a shit down their throat.

The beauty of this is that they can't reasonably go to anyone over this, as it's totally unbelievable and out of character. And will be so horrified of what they just heard that they will leave you alone.