AFAIK, about 40 yrs back, this used to be DR-MAS exp with rake sharing as DR-KOP, KOP-NGP, NGP-KOP, KOP-DR, DR-MAS and MAS-DR. Later when PUNE-KOP was brought under CR, DR-MAS got converted to CSMT-MAS with RSA of MAS-CSMT mail. The other RSA changed to CSMT-KOP, KOP-G, G-KOP, KOP-CSMT.