If I was to create a domain called GenericHelp.com and then create 2 other domains called SubjectMatter1Help.com and SubjectMatter2Help.com and redirect both the Subject Matter domains to the Generic Help domain would this adversely affect the PR for the Generic site?

Note: GenericHelp.com is on a separate IP than the SM domains, but the SM domains are both on the same IP.

Well, you first have to answer the question: What do you expect to gain from this?

If you can expect the two SubjectMatter domains to get a reasonable amount of type-in traffic, then fine, capture and redirect those type-ins to the main domain.

would this adversely affect the PR for the Generic site?
No, not really. PageRank is a calculation that is only concerned with the value of incoming links to specific pages. So, unless each secondary domain has its own backlink profile (something fairly difficult to do with a redirected domain), there will be no negative nor no positive effects.

that would not hurt and unless the other domains came with sites that had traffic and links directing them to the new domian will do little - unless the names are completely differenta dn could get some type in traffic

No, it wont affect much your PR but it could atleast help increase GenericHelp.com's traffic if your SM domains are getting much traffic.

Just use 301 redirects, to be safe...

can point all dns to one but 301 is better

Thank you all for your comments, but I see that this was just a bad idea with little to no benefits.