Operations across rows of a matrix, comparing overlap -

imagine symmetric matrix follows:

   b  c  d    50 0  25 b 50    0  50 c 0  0     50 d 25 50 50  

what i'm trying accomplish dyadic, comparing across 2 nodes see how overlap have other nodes in matrix.

for example, following matrix product need obtain.

   b  c  d    25 25 50 b 25    50 25 c 25 50    0 d 50 25 0  

the value of 25 in [a,b] cell of latter matrix obtained comparing how , b respectfully related c , d. instance:

1. first across top row of top matrix.
2. ignore a's relationship b.
3. a has 0 relationship c. ignore because of 0.
4. a has 25 relationship d. b's relationship d equal or greater number, give 25 credit a. becomes [a,b] cell.

for [b,a] cell, it's similar process:

1. similarly, across second row of matrix.
2. ignore b's relationship a.
3. b has 0 relationship c. ignore because of 0.
4. b has 50 relationship d. node a's relationship d 25, give b credit of 25 in terms of overlap.

conceptually, these relatively straightforward, functions permit these operations? actual matrix has hundreds of nodes, calculating hand not option.