How to set up the Filter?

Select the Email List that you wish to filter. Under List Maintanence select the Email Filter option:
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Enter in a name for the Filter:
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Enter in the values for the Custom Variables based on which you wish to filter the list:
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How to send only to the filtered email addresses?

Under Send Email Invitation select the list and click on the Send Email Invitation button:
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From the Filter drop menu select the saved filter and send:
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See example: