I understand the concern with having pages that don't convert as well outranking your "more important" pages. Fortunately, this is probably one of the better problems you could have. There are two things you can do to take advantage of this situation, assuming these pages exist in subfolders of your site and not as a subdomain or separate site.
First option, optimize the internal links on your resource pages to dirrect users and bots to your homepage and commercial pages that are relevant to the content of that specific resource page. The fewer links you have off these pages the better in order to not dilute the PR that is going to the pages you want to rank.
A second option, is to move the content to your commercial pages, assuming the information make sense to have on those pages, and 301 the resource page to the commercial page. I imagine this is going to be less ideal for users, depending on your site and content, but this should completely avoid the problem you're concerned about. I would only go this route, if option 1 doesn't work and the traffic that is entering your resource pages isn't converting.
And, although I don't know if search engines consider it at all, you have the option of designation a page's priority relative to the rest of your site in the sitemap. So you could set your resource pages' priority to .3 and your commercial pages to .7. But again, I don't know if this is actually used by search engines.