Groovy/Java Library Functions in E1 Orchestrator

Is it possible to reference Groovy/Java code that is defined in another custom script with the referenced code returning one or more values. Effectively I want to set up some functions or subroutines that can be utilised by multiple custom scripts without the need to code them in each calling script.

For example I may have various date handling routines that I want to call, but don't want to have the same code in multiple scripts. We are using E1 Toolset 9.2.5.4.

Thanks

Jonathan