What these people should do, who have people working for them in their houses, is to enable them to pray in congregation, because of the great reward and goodness that that will bring. This is a kind of cooperating in righteousness and piety. Allaah says (interpretation of the meaning):
“Help you one another in Al-Birr and At-Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression”
It is not permissible for them to prevent them from praying in congregation, because praying in congregation is a shar’i obligation, and a shar’i obligation exempts one from work, because obedience to Allaah and His Messenger takes precedence over obedience to any human being. But if this worker is prevented from praying in congregation and he needs his job, then he is excused in this case, because he is being prevented and this is not his choice, rather if he were to leave his work that would cause trouble for him.