Is there any custom setup or even paid third party service that I can use for this? How would I set it up?
What exactly does this mean?
Anyway, all the big mailing companies (spamgrid, hubspam, etc) offer the ability to "lie and import" a list of contacts where you swear on your ancestors that you have permission to send to them.
Anyway.. sendgrid, AWS SES are good places to start.