The American Topical Association (ATA) hosts a platform called “Stamping Ground.” It’s a social media site where topical collectors can share information and ask questions. The Christmas Philatelic Club has a page on Stamping Ground. Take the opportunity to check it out and join, membership in the ATA is not required and there is no cost. This link will take you to the “Guest Membership” page. Existing members can login with your existing credentials.
When on Stamping Ground, click “Groups -> Study Units” and scroll down to you find Christmas Philatelic Club. Or you can click this link.