[NTG-context] Natural Tables---Including a bit of cell style in a \define

I am creating documentation labeling the circuits of electrical and network panels for a project of mine. Enclosed is a minimal example. What I would like is to define two macros: \unused and \spare (\unused referring to a circuit with no breaker installed, while \spare referring to a circuit with a breaker, but no load). I wish these definitions to not only include the represented text and font directives, i.e., {\tt [Unused]}, but also shade the cell in a background color. However, I cannot seem to figure out how to do that. Including the `[background=color,backgroundcolor=gray]' in the \define seems to be expanded back simply as text. Any suggestions? advTHANKSance. -- ----- - Pavneet Arora