There are several populations available in HapMap beyond the original four. Taken from the HapMap display of any genomic region:
Population descriptors:ASW: African ancestry in Southwest USA, CEU: Utah residents with Northern and Western European ancestry from the CEPH collection, CHB: Han Chinese in Beijing, China, CHD: Chinese in Metropolitan Denver, Colorado, GIH: Gujarati Indians in Houston, Texas, JPT: Japanese in Tokyo, Japan, LWK: Luhya in Webuye, Kenya, MEX: Mexican ancestry in Los Angeles, California, MKK: Maasai in Kinyawa, Kenya, TSI: Toscans in Italy, YRI: Yoruba in Ibadan, Nigeria.
perhaps one of these is better suited to your interests.
We work with a Puerto Rican population and it is distinct from Mexican Americans in haplotypes and ethnic ancestry. Thus, while you may be able to find population data that resembles your population or your interests, another population is different and is thus only an approximation, hopefully a good one.
which paper are you referring to?