block specific system calls

im working on a problem in C & Linux(Ubuntu) and one of the requirements of the exercise is to block specific system calls, one of them being read(2).

I know I can block signals, but can I treat a system call as a signal and add it to the block list? For example, in unistd.h read(2) is some number, 63 maybe, can I use that id to add it to the block set using functions defined in signals.h? Ive never heard of someone blocking system calls and havent been able to find any useful info so im kind of guessing around here, help is much appreciated, thanks!