Cross reference values in multiple lists with each other.

Input parameters:

1. L1 → The First list whose items to cross reference.
2. L2 → The Second list whose items to cross reference.
3. Pr → Pairing mechanism to apply.
   • 0 → All
   • 1 → Diagonal
   • 2 → Coincident
   • 3 → Upper Triangle
   • 4 → Upper Triangle Strict
   • 5 → Lower Triangle
   • 6 → Lower Triangle Strict

Output parameters:

1. Gr → Groups consisting of all cross-references value combinations.