Hi Peter,
I suspect you could send them manually at this early stage but it would be a labor intensive effort.
Better would be to include something in your automatic welcome letter to new members, a brief paragraph explaining that all the older messages are archived online at your group's Group.io site and that they may be easily accessed by clicking on the 'Message' button in the lefthand sidebar.
That way those members who are interested in knowing what went before can read thru those earlier messages by simply going to your group's homepage. They'll need to log in but that's quick and easy to do.
OK ¡ª HTH
Paul M.
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