You can build live communities on Twitter using RoundTeam and its automatic retweeting features. Community members have an opportunity to share relevant tweets without following each other directly. The main idea of this approach is to create unique retweet item (#hashtag, keyword or phrase) and configure it to be retweeted from followers of the community Twitter account.
You can engage your followers into a conversation by re-posting their Tweets into community feed. This way everyone in the community will get timely updates.
Refer to the full Community Building Guide for complete information and step-by-step instructions.