State and federal laws require employers to display several posters at the workplace. Posters should be displayed in such a way that each employee can readily see them. Conspicuous Placement
Generally, the requirements have language such as "conspicuously placed" and "readily accessible" to employees. That would mean employees who do not normally get to certain offices would not be served by posters displayed at those offices.
The offices, or sub-offices, where those employees normally congregate would need to have the posters displayed for the benefit of the employees who are served by each such location.
Temporary Work Sites
Posters and other kinds of required notices do not have to be placed in individual locations that are only temporary work sites. For example, construction workers building homes in a subdivision would not need to have posters in each house, but rather only in a company job site trailer for the project.