How to get the first member of a substitution variable?

Hello everyone,

I am trying to get the first member of a substitution variables.

I created a substitution variable called "YearRange" and set it is "FY24:FY28":

So my question is:

In the business rule, how can I substring to get the "FY24" of this variable?

Thanks and have a nice day!

Note: I don't have groovy!