[doublepost=1487026351][/doublepost]I know, old thread. But after quite some online search, I ended up here, trying to solve my problem of pasting a longer list of mobile numbers into iMessage on a Mac. I did come up with an easy way, thanks to mihirwani's advice (#17) how iMessage uses comma (,) as a delimiter. So hopefully it may help future surfers to find a solution.
My lists typically are not stored with a comma (,) attached (they are in Excel or Outlook). I therefore copy my list of mobile phone numbers (including any text that might be associated with the list), into Extractemailaddress.com. I select comma (,) as 'Format / custom separator' and I deselect 'enter at the end of the line'. After Extraction, I can copy the list of mobile numbers directly into iMessage on my Mac. Now iMessage accepts the format for each individual mobile number.