How to send product recommendations to mail chimp users

Hello guys, I am trying to come up with a solution to send email newsletter with product recommendation to our users. This is what I have: 1. User-list on mailchimp. 2. All users segmented into different categories. 3. Products with unique url, price, and description stored in my Parse.com database.

What I need: 1. Find out products for each segment of users and send an email campaign to that segment.

What I have done: 1. Run a cron job to find out products and send it to Mandrill to the targeted segments.

This solution is very slow and takes forever to finish as it is trying to send a transactional email to each user.

Ideally I would like to just get the products list and send it to a campaign on Mailchimp for each segment.

If anyone has an experience in such integration, pointers to it would be much appreciated.

Thanks,