Considering the question to be asked for the pilani campus,
The answer is No for Boys.
While registration everyone is allotted one of the available hostels (Around 5 for freshers) through lottery. Only one of those available hostels (SR bhawan) is completely allotted to the freshers. The rest of the freshers generally share their hostels with seniors.
Campus has only one Girls hostel,
So every girl, whether a senior or a junior share the same hostel.