Only if the underlying forum software has a module that does this and the admin/hosting service has implemented it. Features like that are highly dependent on the hosting package offerings. Such modules can often be additional cost subscription services, and if third party, the hosting company may not offer them.

i've been poking around in the settings behind the scenes.

any changes i make would have an adverse effect on legitimate users.

i haven't given up.
just posting an update to let you know i'm not ignoring the issue.

I hope no one is clicking any links in these posts. Who knows what could be introduced into your computer or phone...etc.
Last week I had my online game account suspended and canceled by Customer Service because someone tried to access my game account. One of the things to do was do a through virus scam on your computer, change password. I did all those as a precaution. It was resolved Sunday evening.
My suggestion to anyone who clicked or clicks any of those spammer post......Run your virus scan (the full through scan) not the quick one. Change your password here and keep a close eye on any sites your CC or Paypal use and of course your bank account.

Thanks so much.