How can I limit a section of code to a single thread?

We have multiple MATLAB users on a single server with 80 cores. This is normally not an issue as the majority of our code runs in parfor loops, however there is a section of code that is not within a parfor loop, and it defaults to using all 80 threads, slowing down everyone else's code.

Is there a way to temporarily force a section of code to be single threaded/just a few cores? The current workaround is placing the block of code into a single parfor on its own, but this isn't ideal as not all functionality is available within a parfor.