I'm building an engagement program with 5 streams.
Each stream is a set of emails for different topics.
Each stream sends an email once a month.
Each stream is available for sales representatives in salesforce to add people to that campaign, trough a smart campaign with a "request campaign" trigger for each stream.
I want to set a limit so sales rep. cant add contacts to more than 3 streams. We don't want anybody to get more than 3 emails per month for this engagement program in general. People can only be subscribed to 3 streams.
How can I achieve this?