Preventing user from invoking shell commands in R language

Is there any form of preventing a user from calling shell commands in R, particularly through the system() function?

My security concern is that I offer to my users an online R environment through RStudio Server. Once logged in, they can execute malicious instructions such as system('cat /etc/passwd').

For instance, in PHP language we can restrict the usage of a group of functions by specifying them in /etc/php.ini configuration file: