Layering shaders

Is there a way to layer multiple shaders, say a blue diffuse and a green diffuse, to different areas of a mesh? I want to use a UV mapped image to tell blender where the green will be and where the blue will be. Is this possible? I can’t figure out a node setup that will accomplish this. Thanks.

Figured it out (I meant with cycles / material nodes, forgot to mention that). Attached: