[TYPO3-mvc] Creating a dynamic back-button for error page

[Frank Mey - NEW.EGO]

Hi list,

I got a "simple" task: Validate a model property depending on the value of another property :).

This is: Property 1 has to be required, if property 2 is empty and vice versa.

My plan is to write a custom validator class but I would like to ask you as experts what would be 
the best point to do this ? Write a model validator or validate it in the controller ?

Thx 4 info,
Frank