sharing document with multiple users but no one can see the total

[lana.b]

hello,
i'm working in project managment department, my Colleagues controls
different types of project, for example person1 controls the tourism sector
projects, person2 controls agriculture projects, etc..
so i want to share an excel document with multiple users, which everyone
fills only the information concerned with his sector. meanwhile user1 cant
modify user2's document but at the end i need to have a master document that
reflects all the data from these documents.
for more clarification, when user1 fills the required feilds. and user2
fills also it will directly reflect to my master document, but user1 cant see
user2.

please help,