I would like to be able to reply all, but I don't see a way to do this.
Currently, there is no reply all feature in Attentive.ly due to limitations in place with Twitter. For example, sending a tweet to over 10 people causes Twitter to flag the tweets as spam and would ultimately result in the accoutn being suspended. As such, you can only send up to 10 direct messages at a time, and queue them up to 100 a day.
For more information on the reply and respond features of the product, please click here.