A common practice amongst users is to use the same mailbox across multiple campaigns. These previously posed situations where there could have been a chance that emails would be sent in very short time gaps from the same mailbox.
Even though the campaign-specific rules were followed, there was no "inter" campaign communication.
With the latest update, you can safely cross-share mailboxes across campaigns by setting a minimum time gap between mailbox and campaign levels w/o hurting any deliverability
This means, there can be times where a lead’s meant to be reached out with a first or follow up email that may be skipped. Our system’s allocation engine works with triggers. These triggers are setup based on your Start-End time in the Schedule section combined with the minimum time gap between emails being sent. At the point of a trigger execution our engine looks for emails to be sent along with the partnered mailboxes.
With the addition of a minimum time gap on an email level, we also consider when the last email from that mailbox was sent, and if it was less than the minimum time gap you set up, that lead+mailbox combo is skipped until the next trigger which may be 5min, 8min (whatever setting you have) away