Add user automatically to Group

Hello everyone,

iam using the Openfire build in DB to host a small Openfire server. I try to find a way to add all user to a specify group. I know this is possible when using the register plug in but i think it only applies to the users which are created through the webpage, not the ones which are create by an client. Is there any way to somehow scan regulary for all users an add them to a group?