Note: This answer addressed the original question that had been asked.
No, adding an adjectivally acting noun to a noun doesn't turn it into a collective noun.
A collective noun is a word for a single thing that is made up of multiple members.
Examples, from Ginger, include:
- Herd – A group of herbivore animals
- Swarm – A group of insects
- Crowd – Usually used to describe a group of people
- Choir – A large, organized group of singers
- Set – A tidy group of matched objects such as dishes; also used to describe rules or a social group of people
- Stack – A group of items neatly laid one on top of another; i.e., a stack of books
Whether or not you precede the noun with another noun that acts to narrow its scope, the status of the noun that's being modified remains the same.
The following are my own examples.
- The crowd. It is already a collective noun.
- The student crowd. It is still a collective noun, but now it's been narrowed to specify a crowd related to students.
- The buildings. This is not a collective noun. It simply refers to physical structures.
- The student buildings. It is still not a collective noun, but it's now referring to buildings designed for students.