Local society email issues

We have four members of the committee who need to be able to send an email to all members of our society, ideally by sending an email to one email address, say allmembers@xxx.com, but not allow anyone else to send emails to this group, and if anyone were to click reply to all, it may only to the sender and not to the whole group.

We use IONOS and it seems we would need to pay an additional £18 a month for this, which seems a lot of money.

Are there other [free or cheaper] solutions which don’t rely on sharing the membership database and cutting and pasting email addresses in the hope everyne does it as a BCC and not in CC?

Thanks for any replies.

James