Difference between secretary and secretariat

Dear teachers,

If sb works for one company. In this company, there are 5 secretaries. He is one of the 5 secretaries.
Their duties are: answer the phone, translation, make contracts, decisions…
These 5 secretaries work together. The leader of these 5 secretaries is secretary to the manager.
So there are all 6 secretaries: 5 secretaries employees and one leader.

Can I say that these 6 persons work in a secretariat?

If no, what is the difference btw secretary and secretariat?

Best regards
Tung Quoc

A secretariat does not even do much typing: 1a. The department administered by a governmental secretary, especially for an international organization. b. The office occupied by such a department. 2. The office or position of a governmental secretary; a governmental administrative office or department.

I think you have a secretarial pool there.