I'm trying to move our emailing campaigns over from a well-known email provider, we'll call 'MailMonkey' (MM), into Zoho.

I'm using a list of contacts from our CRM to create a Campaigns List but...having run campaigns with a very similar data set on 'MM', we have a number of unsubscribers & bounce-backs built up.

I have all these unsubscribers in a CSV file from MM and just need to 'merge' them with my clean list in Campaigns so that anyone who has already unsubscribed is excluded from future emails from Zoho.

Has anyone done this or can help with how this could be achieved? I have attached a simplified visual representation below.