The recent release of iOS 8 may make it necessary to implement some changes to your groups. Because of the long wait time experienced when you try to send messages to large groups, we recommend groups of 100.
If you need to adjust your groups, you can use iCloud to make these changes.
Step 2: Click on the Contacts section of iCloud.
Step 3: Create new groups by dragging and dropping contacts.
Step 4: Pick up your iPhone and open the Mass Text Message app. Tap on the “gear” icon and tap on “Import a Group from Contacts”. Choose the groups that you would like to add to MTM. If there are any ambiguous contacts (with more than 1 mobile number), the app will prompt you to choose which number to add to the group.
Step 5: Begin mass texting. It’s really that simple! You can also do the same iCloud group management in the Contacts application on a Mac. See the Help Menu in Contacts if you need help with that process.