Call Zoho Creator function from CRM function?

Is there a way to call Creator custom functions from inside a CRM custom function?

Since CRM custom functions can only have a return type of void, I am wondering if I can write a custom function in Creator with a different return type (like int, or string) and then call that function from a CRM custom function?

So far it seems that the 'call function' line in CRM custom functions can only call other CRM custom functions, which all must have return type of void.

Am I missing something?