Matching several indexes

I have a large set of data in which I need to compare several samples in different tests and under varying conditions. I am looking for a way to pair and analyze these easily. As an example, lets say I have Samples (S) a, b, and c, which undergo tests (T) 1 and 2, under conditions (C) x, y and z, which output results (R) R1 and R2.

S   T   C   R1  R2 a   1   x   2.9 a   1   y   2.6 a   1   z   8.7 a   2   x   9.4 0.372 a   2   y   8.1 0.208 a   2   z   7.6 0.154 b   1   x   7.5 b   1   y   7.3 b   1   z   1.7 b   2   x   3.9 0.213 b   2   y   7.9 0.435 b   2   z   2.5 0.294 c   1   x   6.2 c   1   y   1.8 c   1   z   6.3 c   2   x   1.5 0.246 c   2   y   6.0 0.496 c   2   z   1.7 0.167 

The tests have different outputs, and I need to apply specific functions depending on the test. Such as:

Test1[a,b] = R1a/R1b Test2[a,b] = R1a/R2a - R1b/R2b 

The tests should only be applied to samples with matching conditions, but each sample should be paired. So a result would be:

S1  S2  T   C   R a   b   1   x   2.9/7.5 a   c   1   x   2.9/6.2 a   b   2   x   9.4/0.372-3.9/0.213 a   c   2   x   9.4/0.372-1.5/0.246 a   b   1   y   2.6/7.3 ... 

I’ve been trying to get this right for a while and just end up confusing myself. Anyone have a solution or suggestions? If you want an easily copyable format of the example:

{{S,T,C,R1,R2},{a,1,x,2.9},{a,1,y,2.6},{a,1,z,8.7},{a,2,x,9.4,0.372},{a,2,y,8.1,0.208},{a,2,z,7.6,0.154},{b,1,x,7.5},{b,1,y,7.3},{b,1,z,1.7},{b,2,x,3.9,0.213},{b,2,y,7.9,0.435},{b,2,z,2.5,0.294},{c,1,x,6.2},{c,1,y,1.8},{c,1,z,6.3},{c,2,x,1.5,0.246},{c,2,y,6.,0.496},{c,2,z,1.7,0.167}}