The acquisition takes QHotels's portfolio to 21.
Michael Purtill, QHotels's managing director said the company would be looking to develop Marston's health and leisure brand Reflections across the whole group.
He added a major investment and development plan for the extended group would be announced in the New Year.
QHotels was formed in 2003 by Michael Purtill, Ian Goulding and David Taylor in partnership with investment company Alchemy Partners.
Property agents Jones Lang LaSalle hotels handled the sale.
By Emily Manson