This is going to be difficult, because you're in the domain of patent trolls, legal firms that specialize in very tight arguments and skillful identification of their prey.
Before I go any further, this disclaimer: I am not a lawyer, I don't even play one on TV. This article must not be construed as legal advice, and you need to consult with your attorneys before taking action on the issues raised here. Yes, my lawyer made me write this.
Patent Mills
All too often, the Patent and Trademark Office grants patents that are overly broad and seem to ignore much of prior art. I used to work for a software company that had been issued a patent that could have covered most of distributed computing.
Recently, I came across a single patent that seemed to cover all the most interesting parts of CRM and ecommerce. The fact that much of what the patent claimed as a new innovation had been bundled in Windows 95 didn't seem to bother the PTO's patent examiner. Yet this patent is now being used to shake down ecommerce companies all across the U.S. The fact that none of them knew about this patent when they built their ecommerce systems doesn't matter: the royalties and the damages probably will be paid. Even if the alleged infringers win their cases, at $500 an hour the lawyers and expert witnesses get expensive.