email while creating a new group

Hello !
I am in the phase of setting Groupjive in my site. 

I am wondering if it is possible to send an email to all registered users while a new group is created. Currently, It is an activity and a notification. Is there a setting for this or should be something doable with autoaction ?

CB GroupJive doesn't have that functionality so no it's not doable without implementing it yourself. It however can be implemented using CB Auto Actions. The below should work.

Global
Triggers: gj_onAfterCreateGroup
Type: Email
User: Automatic
Access: Everybody
Action
To: query
To Query: Subject: EMAIL_SUBJECT_HERE
Body: EMAIL_MESSAGE_HERE

That should email every user when a group is created. I would recommend caution with this. It'd be easy to spam users with too many emails by doing this and could result in your email domain being blacklisted if too many people report you as spam.

Thank you, I had a first trial sounding good ! Thank you also for the recommandation about email flooding, it's OK in my case because there will be only few events and a short list of users all registered and aware.

I have 2 questions ( i did my best to read documentation and help bubbles  but it is not comprehensive enough for me without your help)

How to use conditions and is it necessary to choose one ?

I do not find the way to use substitutions for the email ( such as username,groupname....)- is there a list somewhere and are they available or must do something to make it available ?
EDIT: It seems to be the use of references (variable 1, 2...) in the parameters of the related autoaction. But i still don't know how to use it