You would need to treat the money market accounts as transaction accounts for Reg D purposes before you gave POS access. I do think that you could allow a money market to be a secondary type account for in-person cash withdrawal purposes (PIN based) like a savings account. You just could not permit unlimited POS transactions if the MMA accounts are classed as limited transaction accounts.
_________________________
Life without Jesus is like an unsharpened pencil - it has no point.