You can't really do that. In Hubspot terms, making someone a marketing contact makes them eligible to be sent marketing emails. So the first emails that would be sent would have to be transactional (an addon in Hubspot) and opens are really inconsistent in email marketing because it requires that the platforms accurately report this information and with updates like the most recent from iOS the tracking is blocked for privacy reasons.
What sounds closer to what you want is engaged contacts. So you would make all contacts that you want to email to marketing contacts, but you only want to send to engaged contacts. Unfortunately this feature does not really work in Hubspot, but you can look at their activity or score and make someone an engaged contact and put them in an active list that you use as criteria for mailing to contacts.
You can't really do that. In Hubspot terms, making someone a marketing contact makes them eligible to be sent marketing emails. So the first emails that would be sent would have to be transactional (an addon in Hubspot) and opens are really inconsistent in email marketing because it requires that the platforms accurately report this information and with updates like the most recent from iOS the tracking is blocked for privacy reasons.
What sounds closer to what you want is engaged contacts. So you would make all contacts that you want to email to marketing contacts, but you only want to send to engaged contacts. Unfortunately this feature does not really work in Hubspot, but you can look at their activity or score and make someone an engaged contact and put them in an active list that you use as criteria for mailing to contacts.