Table Script Common Functions File

SUGGESTED

I'm sure that it is possible to create a common server side JavaScript file for table script functions but I can find no reference to this.  Does anyone know how to do this?  I thought there was a system parameter for this but I can't find it.  

At the moment I am creating some table scripts which involve quotes and orders, with some functions which are common to the both of them.  Rather than have two copies of the exact same function it would be ideal to have one copy of that function which can be referenced from both the quotes and orders table script.