It is possible to set up multiple FTP accounts with each only being able to access a specific folder? I have been looking at how to do this and I have not found anything about it,
You mean you want to be able to define which folder can be accessed with the FTP account? No, that's not possible.
You could create a new user on the shell with your ftp directory as his homedir. Make sure you use a user ID below 10000 (as ISPConfig's users start at 10000); you should also add the new username to /home/admispconfig/ispconfig/users to avoid that you create the same user again with ISPConfig.