If your employees are in transit for 11 hours and there is no other available flight available, unless stated in the terms and conditions, Qatar will provide accommodation for your employees overnight. On arriving at Doha they simply need to contact one of the ground staff who will direct them to the overnight hotel accomodation section. In relation to paying for a visa it is not required, because the staff will simply give your employees a 24 hour entry visa for free. If your ticket conditions exclude accommodation then you need to contact your local Qatar Office who will arrange accommodation for 100 dollars per night in economy or 150 dollars in business class. If you are excluded from overnight accommodation it might be worth buying slightly more expensive tickets in your case, because when you add everything up it may be cheaper in the long run.