Yes that should work. You can have something like this:
Surgery
departmentFloorSpace (field, non-repeating)
areas (group, repeating)
areaName (field, non-repeating)
areaFloorSpace (field, non-repeating)
rooms (group, repeating)
autoNumber, etc.
And plenty of other possibilities. Yet again, you can reference this "areas" node type if you have more than one department with several areas.
And don't be afraid to re-use (reference) field names that you're already using in the elsewhere in the data source, using the method I described earlier (right-click, etc.). Your data source could even look like this:
Surgery
totalArea
areas (group, repeating)
autoNumber
areaName
totalArea
rooms (group, repeating)
autoNumber
roomName
totalArea
...
Here Surgery, areas, and rooms all have a field called totalArea, and areas and rooms both have a field called autoNumber, but the fields each serve their own logistical purpose based on their place in the datasource, so they still make sense.