If this is the case and the difference between Isha and Fajr is only 2 or 3 hours, it is permissible to join Isha to Maghrib providing that this is done only when a person has work. In case of weekends, one should pray Isha on time.

Can we make maghreb and isha together if in my country isha is very late like 12 at night and fajr is at 3am in the morning?some people works so is very hard for them to respect the hours of preying.?and if someone for example cant stay until 11 or12?