contribution map in maya 2009
 

A pass contribution map associates a subset of the lights and renderable objects in the scene to one or more render passes. When rendering a given render layer, only the pass contribution maps linked to the layer are applied.
Render passes that are not connected to any objects through pass contribution maps are implicitly associated to all objects.
Pass Contribution Map Options Active Enable this attribute to use the pass contribution map.
Open Render Settings Click this button to open the Render Settings window.

so if i have more than one contribution pass suppose 3 i.e. keylight , fill light and rim light, and i want to render each light dedicated it each contribution map individually which is under my render_layer1 and i have diffuse , specular and shadow pass then i associate diffuse and specular with all above 3 contribution map and i add shadow pass to the keylight so what would i get ? 3 passes combination rendered out ? i.e. combination of 3 lights under my render_layer1 or render passes(diffuse,specular and shadow) for each of contribution map which are (keylight , fillLight,RimLight).

please help...