Relook at your problem.
I gather you probably have all the address in Numbers because you had them in Excel?
Work on getting them into Address Book where they will become more useful.
In Address Book's help
*Importing contacts*
Address Book can import contact information that you save or export from other applications in vCard, LDIF, tab-delimited, and comma-separated (CSV) formats.
You can export addresses in LDIF format from Netscape, and vCards from Palm Desktop, Entourage, Outlook, and others. You can export text files in tab-delimited or CSV format from most databases.
*To import addresses from other applications:*
*1 Export addresses from the other application* in vCard, LDIF, tab-delimited, or comma-separated (CSV) format.
■ When exporting tab-delimited or CSV files, you may want to note the order of the information fields. If the file doesn’t contain labels, you can refer to your notes to manually identify the fields in a later step.
■ When exporting from Palm Desktop, use the default column layout.
■ If the application you’re exporting from supports it, export vCards that include multiple contacts to speed up importing. For example, in Outlook select all of your contacts and choose to forward them as vCards. Send the email message, which includes a vCard attachment for each selected contact, to yourself on your Mac computer. In Mail, save the vCard attachments, and then use Address Book to import them.
*2 Verify exported .txt or CSV files* using a text editing application such as TextEdit.
■ Make sure there are no line breaks within a contact’s information, which can cause the import to fail. Remove any line breaks you find.
■ Make sure that fields in a .txt or tab-delimited file are separated by a tab, and fields in a CSV file are separated by a comma, instead of by quotes or another character. Do not include spaces before or after tabs and commas.
■ Make sure all addresses have the same number of fields; add empty fields, if necessary.
*3 In Address Book* choose File > Import, and then choose the format of the exported file. Choose “Text File” for a tab-delimited or CSV file.
*4 Select the file* that contains the exported addresses and click Open.
*5 If you are importing a text file* use the pop-up menus in the Text File Import dialog to specify how to import the data.
■ If the first record contains labels instead of contact information, select the “Ignore first card” checkbox.
■ Use the left and right arrows to see different records in the file you’re importing, to help you determine how to set the pop-up menus.
■ If you don’t want to import a field, set the pop-up menu to “Do not import.”
■ To set the pop-up menus for address fields, choose the type of address (home, work, or other) in the pop-up menu next to the first item of the address. Then use the address pop-up menus that appear to choose the corresponding data for each address field.
*Then in Automator:*
+Actions > Mail > Group Mailer+
uses Addresses from your Address Book to send multiple emails.
