mod_groups_internal: allow force-emitting group member addition events This is useful when a new plugin was loaded which handles that event to add some value. Then the command can be called (**not** from the plugin but from an upcoming admin shell module) to synchronise things.

This module allows sending a message to another MUC room.

    @other-room: hello

The message will appear in the other room as as

    <first-room/You> hello