I have recently moved to the Xfinity email app from Outlook. One of the things Outlook did very well was to route incoming emails into subfolders based on rules that I set up.
I have set up subfolders in the email app, and set up rules to move incoming email from certain senders into certain folders, but the rules don't appear to be working. I called Customer Support and he was no help. He wanted me to delete the subfolders, delete the rules, then start again. When I asked him, "What good would that do?" he didn't have an answer.
Run a test for yourself-------------using some other email address you have, say from Yahoo, Gmail or something else, set up a filter using that address as the filter criteria to send it to a folder in the Comcast account. Does it work OK? Make sure you click on "Save" at the bottom of the box when you have filled in the filter information.