Comparing Columns with Matching Results Listed in One Cell

Thanks for the quick response. I will try to give a simplified example of what I need. If I had the following in columns A-D, I would like to be able to get the comparison results listed in E as shown below.

	A	B	C	D	E
1	x	x	y	x	x,z	(Comparison matches between columns A and B)
2	y	z	z	y	y,z	(Comparison matches between columns A and C)
3	z				x,y	(Comparison matches between columns A and D)
4					z	(Comparison matches between columns B and C)
5					x	(Comparison matches between columns B and D)
6					y	(Comparison matches between columns C and D)

I hope this helps explain what I need.

Thanks again,
Chad