Apple Fax - Manual (Page 43)

If you select multiple faxes, the button is named Merge. It
lets you combine several faxes into a single fax and send the
combined document to one or more recipients.
When you select one or more faxes and click Resend,
Readdress, or Merge, a window similar to the Quick Fax
window appears.
You can fill in or change the various options and then click
Resend, Readdress, or Merge.
30 Chapter 2