A feature that would allow different campaigns to run through different API keys or providers

Posting from GH: https://github.com/mautic/mautic/issues/6047


A feature that would allow me to define which provider/subaccount/IP pool to run a campaign through.

Campaign A through SparkPost/Subaccount A(IP pool 1)
Campaign B through SparkPost/Subaccount B(IP pool 2)
Campaign C through SES