Compound letters in Bengali keyboard

Hi, does anyone know how to write compound letters (juktakkhor) in the Bengali keyboard on MacOS? For example the word for birthday (jonmodin), requires a juktakkhor between the letters "n" and "m". I am using the Bangla - QWERTY keyboard, and it does not happen automatically (i.e. I keep getting the letters as separate instead of the correct spelling). Does anyone know how to do this? If not, what is Apple doing to support this? I am using a MacOS Monterey device.