Research of an accomodation in Bristol

Hello, we are 5 french students who will do their internship at Filton for 3 months. We are struggling to find an accomodation to do a collocation together. We would stay from mid june to mid september. But when we ask for a house, they don't want to deal with us because we won't be there for a whole year.
Do you have an idea where could we find a short-term rental near to Filton for 5 students?
Thank you for your help.