Model manipulation before every call

Hello! I am hoping for advice on how to best approach my problem. Strategies or tips.

I have a website with repeating events & classes. They all repeat using iCal standard, and I decided to calculate each event, rather than store each instance independently in the database. So everytime I get an event, I have to run functions (that I currently have swept under the rug in a Trait) that calculate the instance of the event with a given date in the route uri.

So my question, is whether it's possible to run these calculations BEFORE the model hits the controller. Unfortunately these calculations need a composer package to run... In case that's important.

My urls related to events all look like:

Route::get('/{eventsOrClasses}/{event}-{slug}/{date}', EventController@show);

(fyi: since events and classes run exactly the same, I use the eventsOrClasses variable to switch from an Event model to a Class model which both extend the same base class. I do this switch with route model binding checks)

I appreciate any insight you can give me!