Plotmatrix of different categories

Hi I have a New1=150*4 double and another New2=150*1 double. Rows 1-50, 51-100 and 101-150 each have one specific category, say A, B and C shown in New2 .I would like to plotmatrix New1 (in a 16-house figure) and also have the labels on that figure from New2. How should I use the code plotmatrix or gplotmatrix?