XY scatter plot: Third variable determines color of plots/line

Hello all,
Similar to the thinking of three-dimensional graph types (I have XL 2003), is there a way for a third variable to determine the color of the plot? Furthermore, can the color of the line segment connecting plots be determined by the color of the plots it connects? For example, if to consecutive plots are yellow, the line connecting them is yellow. If one plot is green, and the next is blue, the line connecting them fades from green to blue. Attached is a simplified version, with the key for the "Z-variable" showing color designations.... My example is attached