Currently this is not a feature with Sphere.

Dynamic Content can only be based on: 
Registration Types
Standard Profile Fields
Segmentation
Custom Event Fields

Blackbaud has an idea bank our clients can go to and list any suggestions they have for our programs. You can go to http://sphere.uservoice.com/forums/143074-sphere-product-whiteboard to enter suggestions and vote for you favorite suggestions as well. This is a direct line to our programming team and they look at this for enhancements to the software.