With this approach every incoming email 📨 is duplicated and sent to every member of multisig to their individual mailbox.
There are two variants in this approach.
In this variant only receiving emails is possible. Emails are distributed to members of Multisig and that's it.
In this variant members of multisig, when they want to send and email they have additional email address available: firstname.lastname@example.org, that they can use for sending email. Those outgoing email would be also sent to member mailboxes to keep the conversation in sync for everyone.
Optionally each outgoing email would be annotated with information which member sent it.
In this solution multisig wallet would have a dedicated mailbox and all messages would be directed to it.
Each member of multisig would be able to login to this mailbox and use it as their individual one.