Sampling from a set

Hi

Given I have a set, my aim is to sample every combination of two samples of size n, which are disjoint.

One example: The set would be {a,b,c,d,e,f,g} and the size would be 3, then I would have: 1. (a,b,c) and (d,e,f) 2. (a,b,c) and (e,f,g) 3. (a,b,d) and (e,f,g) 4. (a,b,d) and (d,e,f) 5. (a,b,d) and (d,e,g)

etc. etc.

Thanks