To message all of the participants of a trip at once, just follow these easy steps!
1. Go to your "Manage Trip" dashboard by clicking on "My Trips" and then on "Manage Trip".
2. Navigate to the "Messages" section, click on "New Message" and choose "Message All Participants" from the menu.
You can now customize the subject line, sender, message, and reply address in the dialogue box. Make sure that "Send To" is set at "All Participants".
When you click "Send Message", your message will be sent to all of your participants.