Option to send mail to all attendees of an event

Thanks Bluefox for your answer.
I had an idea which could solve the mailing :
if I could update a CB custom field (Attending : Yes / No) when submitting attending in JEM, then I could base my Acymailing Filter on the CB custom field...

could you give me informations about the file to enhance with something updating CB tables with JEM data ?
or could it be done through a plugin ?
I'm able to program in PHP and would love to contribute to the community.

in the mailer plugin 2.1.5 is the possibility to activate the sending of a notification to all attendees of an event when there is a change in event. Perhaps this helps a bit.

Thanks for your reply,
1) what is a change ?
Could it be a save without modification, to resend the mailing ?

2) I understand that reminders could be sent that way to all registered attendees.

3) I understand that I could modify mailer plugin to insert modification code for my CB custom field.
Another option could be a CRON to synchronize JEM data with CB data for all users.
Do you have ideas about JEM table to read for that ?

1) what is a change ?
Could it be a save without modification, to resend the mailing ?

yes, I just tried in frontend, I opened an event in frontend to edit, I didn't chang anything and saved. The attendees got an email with the notification that something was changed in this event!

(this can be bad: If you only change a typo in event details, all attendees get an email.

If this can help others, I discovered in AcyMail plugins a perfect one for my purpose :
www.acyba.com/acymailing/309-acymailing-plugin-universalfilter.html
Thanks