Instead of having to type out or copy and paste the same text to multiple people, Google Voice allows you to send one SMS message to up to five recipients. You still receive responses as separate texts, so the resulting conversation you have with each person remains private.
Entering Multiple Recipients
Click the “Text” button to open the SMS message window. Type the recipients’ phone numbers in the "To" box and separate each one with a comma. Alternatively, you can enter the names of people in your Google contacts list, again separated by commas.
Creating and Sending the Message
Enter your note in the “Message” box as usual and click the “Send” button to deliver the text. Although the character counter will eventually read, “Really?,” when you exceed the 160 character SMS limit, Google actually breaks long messages up, so your recipients will receive consecutive texts.