Is $EDITOR set up in your UNIX environment - i.e. is that what is causing it to be set? If so, maybe you can set that environment variable in your personal .cshrc/.login or .bashrc - whichever shell you're using.
Most companies have something set up in their central .cdsinit file to look for local customization files too, typically in your working directory or home directory. The default behaviour is that virtuoso looks first in the installation in <ICinstDir>/tools/dfII/local, then in working dir, then in home dir. The first that is found is loaded. Alternatively it can use the Cadence Search File mechanism (sometimes known as setup.loc - search in the documentation for more details). However, in all cases, it loads just the first found - and you have to add code into the .cdsinit to look for local files if you want additional places to look.
So your central file could have:
or similar to look for a personal .cdsinit file.