Bulk sync to Mailchimp
If you want to do a bulk sync, it works very similar to the single sync, follow these steps.
Navigate to your reporting page (make sure you are in version 2)
Use the filter to refine the list you want to send over
Click the purple "Actions" button
Click "Sync Contacts"
Choose Mailchimp from the list
Select which Mailchimp lists these contacts should be placed
Hit sync