MVVM, two DataSources, one element

[Joshua]

Okay, this is a slightly complicated scenario, but will be common in my team's project. Basically, I want to use MVVM and the new declarative style to set up a plugin that wraps around DropDownList. Internally, the plugin uses a DataSource to populate the DropDownList with all its available options. The plugin will be used inside pages and other plugins which will also use MVVM to set its default value using another DataSource. 

Now my question is, is it even possible to do this in the new declarative style? If so, then how? In particular, how do I make it so that my plugin can hookup to the outer MVVM's settings for its value?

Any help would be greatly appreciated.