Am I limited to binding between a view and a view-model?

I often need to share a value between different parts of my UI, for example to keep two views in sync. To do that, I want to be able to bind the view-models behind those views to the value I need to share so that each view-model can track changes to the shared value and report those changes to its view.



Typically, the shared value is encapsulated in a service whose purpose is to share data. The bindings would look like this:



context service

|

+--- view-model --- view

|

+--- view-model --- view



Can I set up this kind of view-model-to-service binding using the new facilities in Ext JS 5 or can I only bind views to view-models? If I can only bind views to view-models, what motivated the decision not to support a more general-purpose binding mechanism between objects?



thanks