List of contacts from list of companies

Commenting to upvote this as well. We have some organization-based subscriptions that are tracked via a custom object associated to the company. But it’s the individual contacts associated with those companies that we need to send the emails to when there is new content in these subscriptions. Can’t figure out a way to pull a list of those contacts. Workflows don’t even work (at least what we’ve tried so far) because a workflow has to be contact-based OR company-based.