The process in which a relatively unspecialized cell acquires specialized features of a mesonephric glomerular epithelial cell. Mesonephric glomerular epithelial cells are specialized epithelial cells that form part of the mesonephric glomerulus; there are two types, mesonephric glomerular parietal epithelial cells and mesonephric glomerular visceral epithelial cells. [ GOC:mtg_kidney_jan10 ]