[movingahead]

They did for prices ranging from $1 - $2 per month. But text messaging does not do groups remotely as well as Whatsapp does.

[balladeer]

You can use it do group thing but then every message sent to group will charged as: cost of one SMS x number of users in the group.

That charge will come to each user of the group whenever a message (%160 chars) is sent.