Ask Al: Group mail is being blocked, what do I do?

Recently, a reader wrote in with the following question:

I host an email group of about 450 people who share a common autoimmune medical condition. I send/receive email through a Gmail account set up in Windows Live Mail on a home PC. My ISP is RCN.  Recently, any emails sent to any group member using an AOL or account are being blocked by AOL. I sent an email to AOL asking to not be blocked and my request was denied with little feedback as to why. I was then pointed to recent changes concerning DMARC and FBL. I generated an AOL account just for those members to get the information they need but this is an awkward way to send emails, using two separate accounts.