Invoking scripts from external files

Hi,
Is it possible to invoke arbitrary scripts(scripts without any class or methods) from an external file inside a groovy step?

For example:
If i have a few lines of script that I need to use inside multiple groovy steps, can I store it in an external file and invoke them inside a groovy step whenever required?
So if there are any changes to the external script, I can just change in the external file alone rather than changing in every groovy step?

Thanks