Comcast.net email confusion

Yes, quite easily.

In your email Account setup, set the mail program on each machine to "Leave mail on server" for 5 days (alternative wording: "Delete files from server after 5 days") This can usually be found behind the Server or Advanced or More options button, depending on the mail programs you are using.

Now all you have to do is make sure that each machine checks the mail at least once every 5 days -- the mail will still be in the POP3 mailbox even if machine A has already read it. Adjust the number of days to what suits you. Reduce the number of days if you get a lot of mail and start to overflow your mailbox Mb limit.

PS: this also allows you to check your past 5 days worth of mail via Web mail from work or elsewhere, if Comcast offers web mail access.