Pipe Connector geometry

Attachment 89480I'm trying to modify a family for Revit MEP 2012. This family for a fan coil unit has several family types nested within the family. Each family type is for a different fan capacity. Each family type has pipe connectors connected to extrusions. The geometry of the fan coil unit cabinet is different for each family type. Is there a way to constrain the pipe connectors and their associated extrusions to the cabinet work face so the connectors will change position with the changing cabinet geometry? The attached image shows where I would like the connectors to be for all of the different family types. At present, as soon as I change from one family type to another, the pipe connectors are out of position. I appreciate any suggestions.

Assuming that all the constraints are correct, there is another issue about connectors and nested families with several types. If you want the connectors to be in place all the time, add all the types you need to the nested families BEFORE creating the connections on the faces of those nested families in the host family. If you add more types after having created the connectos, the connectors will lose their association to the nested faces.
Again, assuming that all the constraints are correct, the issue can be solved by erasing the connectors and placing them again. But, if you add more types to the nested families, the issue will happen again. :)