FACULTY is complete word for both single & multiple teachers as a collective Noun. However, if you are referring multiple organizations or Universities... FACULTIES is suitable word to refer different teachers from different Universities as a plural form of collective noun.

Does faculty have a plural?

faculty, faculties Lowercase. Faculty is a mass (collective) noun—one that denotes something uncountable because it refers to an indeterminate aggregation of people. As the subject of a sentence, a mass noun usually takes a singular verb. But in a collective sense, it may take either a singular or a plural verb form.

Is it faculty or faculty members?

We say 'he's a faculty member' to mean he's in, say, the Arts Faculty. But we now also have the more American use to mean he's an academic staff member (our traditional term) in a university.