Excel2003
I have a page containing this formula in Column GF:
=AVERAGE((BD4-BE4),(BH4-BI4),(BL4-BM4))
How can I check each range for 0 before performing the calculation?

If any of the cells contain 0, I want to exclude it from the average.

ex:
BD4 =4,BE4 =2,BH4 =4,BI4 =2,BL4 =4,BM4 =2
Average = 2
If any of these cells = 0, remove it and its accompanying cell from the
Average formula.
BD4 =4,BE4 =2,BH4 =0,BI4 =2,BL4 =4,BM4 =2
Average = 2