I am attempting to determine whether shared alleles reflect incomplete lineage sorting or hybridization in my data from three species that are all known to interbreed. Knowing that the ABBA-BABA tests are designed to detect introgression amongst two populations, I’m wondering if the assumptions would hold with three introgressing populations. If introgression between two populations is expected to result in a higher proportion of either ABBA or BABA patterns, how might the addition of a third introgressing group affect the ABBA-BABA patterns and how would that change how they are interpreted?