Hello. Just read over your project application. My name is Shelingholmes, I am MailChimp developer, 4 years of experiences in mailchimp. Fields of expertises are API, integrations, and customizations. I have done a lot of Mailchimp project so I am pretty sure could done the segmentation for yours marketing need.
MailChimp has provide a Great API in any cases their users do a customizations, whether its segmentation, grouping, or lists management. I don't know further details about your requirements, But thing I am sure, if its wasn't something that can't do in mailchimp general features, then the API should be able to make it.
For consideration, Please take a moment to visit my profile page, there are reviews and portfolio related MailChimp here.
Thank you, and
Regards,
Shelingholmes