Yes. MNTN lets you create retargeting audiences to target with your campaigns. You can setup an unlimited amount of audiences.
Audiences are created using the MNTN's Audience Builder. When you place the MNTN pixel on your website, you start accumulating data on all your site visitors behaviors. Using the Audience Builder, you can choose from numerous behavioral criteria to define the audiences you want to target (e.g. time, activity or location).
Once defined, you can choose these audience segments during your campaign setup.
To find out more read all about How to setup a New Retargeting Audience.