Go through the following steps to add a group:
1. Go to SMS from the Panel. Select Phonebook from the sidebar of the SMS panel and click on the Add new group option.
2. Type the group name you wish to choose and press ENTER.
3. You may add contacts individually by filling in the details or by directly importing a CSV file of your stored contacts.
Also, there is no limit on importing contacts. You may import any number of contacts in one go.
NOTE: The only restriction is that the file size should be limited to 20 MB.