Completely Secure Membership App for an Environmental Activist Group?

#1

People,

Is what I asked in the Subject already possible? If not, how difficult would it be? (I am old school C, bash and Ruby more recently).

I am thinking of something resembling a mailing list consisting of groups and sub groups, sub sub groups etc.

Thanks,
Phil.

#2

There is for example blockslack https://app-center.openintents.org/appco/1018