I'm currently traveling overseas, and I'm texting my family while i'm away. Will they get charged extra for responding to my texts?

I have ATT as my wireless carrier, and I'm paying a small additional fee to have my international data while I'm away. I'm wondering, while I text my family in a group chat, my end is already covered by the international plan. Will my family be billed if they respond to my texts that are coming from overseas?