You might get a better response if you clarify what you hope to achieve by doing this. Adding more local folders is rather straightforward.

See https://addons.thunderbird.net/en-us/thunderbird/addon/localfolder/

https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

I use the local folder on my account to save emails without being on the server and reduces the space on the server. What we would like to do is create an additional local folder that we can point to our shared drive and can be used by all the accounts

You may be able to manage that at a technical level, but Thunderbird has no conflict/version management so necessary for shared files. If you change or add something to the same folder at the same time as someone else corruption will most likely be the result. How or when that will become apparent is another issue all in itself.