The school is preventing them from praying Jumu‘ah and offering other prayers in congregation; what should they do?
Question

                In my country there is a law that implies secularism between religion and school. It hadnt been implied until recently when its implied our school forbade us from praying zuhur go to juma. Every Muslim student stopped praying because they were afraid of the school board they didn't even ask why the were forbidden, but I collected signatures of students asking to pray and presented it to the academic principal. He answered me politely that this is beyond his capability because it's the law and if he breaks it, he will face consequences from the government. What should I do? I have applied for this year national exam under this school and can't change to another school that is Islamic school (the rule allows only religious schools to practice their religion in school) until I take this exam. (there are about 3 months left for exam).
Praise be to Allah.We appreciate your eagerness to perform the rituals of your religion, and we ask Allah to make you steadfast and help you. 
What is required of the Muslim is to regularly offer the prayers at the proper times, and to keep away from schools that do not allow him to do that, so as to protect his religious commitment, because prayer is the foundation of Islam and anything that distracts from doing it is not permissible.
End quote from Fataawa al-Lajnah ad-Daa’imah, 7/41 
Based on that, whoever is able to move to another school where he can pray Zuhr and Jumu‘ah, must do that. Whoever is not able to move should strive to offer Zuhr prayer at the proper time even if he prays on his own; if he is not able to do that, then he may put it together with ‘Asr prayer. 
Similarly, in the case of Jumu‘ah prayer, it is waived in his case if he has done all he can to offer it; if he is not able to do that, then there is nothing wrong with him praying it as Zuhr. 
The scholars have stated that one of the excuses for not praying Jumu‘ah or offering prayers in congregation is fear of harm from an unjust ruler or of a negative impact on his livelihood. 
Imaam ash-Shaafa‘i (may Allah have mercy on him) said: 
If he is afraid that if he goes out for Jumu‘ah, the ruler may detain him unlawfully, then he may stay away from Jumu‘ah.
End quote from al-Umm, 1/218 
Al-Mirdaawi (may Allah have mercy on him) said: One of the valid excuses for not praying Jumu‘ah or offering prayers in congregation is fear of a negative impact on his livelihood that he needs or if he is hired to guard some property (and cannot leave it).
End quote from al-Insaaf, 2/301 
And Allah knows best.