Think of the word 'suite' as being a collective noun, similar to 'a set', which is used when talking about rooms. A 'suite of rooms' is a set of rooms grouped together for a particular purpose. You can have 'a suite of rooms' in a hotel, for example, which might comprise a bedroom or two, bathrooms and study or sitting room. As 'suite' actually means 'group', the idea of 'a group of suites' ( a group of groups?) is little strange.

It usually means several interconnected rooms, for example, a lounge, bedroom and bathroom/WC, in a hotel. It could refer to a group of rooms in a conference centre, in this case, classrooms, offices, and lecture rooms.