I have a naive question

I have an influence diagram matching a real-world experiment. This diagram has only one utility node, and in the experiment I can observe the value corresponding to this utility node. Since the utility node maps utility value to the values in the parents node in the odometer-like style, what to do when the same combination of values in the parents have two different utilities? Should I use this node as utility node at all?
Cheers,
Nikola