The short answer is you probably want to setup parked domains, and it looks more like you've done addon domains (or something else) - you are using cPanel right?

Lets go back to the start and get it clear: do you want hanginoutforums.org and forums.hanginoutforums.org going to the same place or different? (Ignore the www versions for now.)

If the same what is the intent of having the forums subdomain?

Do you have the ability to view/edit DNS records directly?

You could do it with three distinct accounts, but I do have a similar setup myself that works all under a single account. It seems I've done that using subdomains and addons

So the main account has accountdomain.com with the document root /home/account/public_html

Then I have subdomains for that setup outside of public_html:
other1.accountdomain.com -> /home/account/other1/www
other2.accountdomain.com -> /home/account/other2/www

I don't use those subdomains though - I have the relevant domains setup as addon domains:
other1.com -> /home/account/other1/www
other2.com -> /home/account/other2/www

I think if you setup hangingoutforums.org and forums.hangingoutforums.org in that way (pointing to whatever the appropriate directories are), then www.hangingoutforums.org will be handled by cPanel, and you can alias the www.forums.etc version to the non-www version (either using cPanel or setting up a CNAME DNS record), and it should all do what you want.

I don't know if I've explained that very well - let me know if not.