I think your grandfather or great grandfather was in Hardali, Khulna (now in Bangladesh).
Our family also hailed from Mahinagar and one of our ancestor comes to Khulna.
my father - Ranendra narayan Bose.
Grand Father - Atul Krishna Bose.
Grand Mother - Snehalota Bose.
Great Grand Father - Janaki Nath Bose.
One of my Uncle Mr. Deb Kumar Bose wrote a book (name "MAA") on histry of our family. There he stated about the histry, but unfortunately I lost that copy. if I can get any information about any link between us please inform to my ID- "rajnbose@gmail.com".