Execute a method after relationship grid is loaded

hi,

I need to update the state of some relationship grid fields when they are loaded.
For example set a field as link to a folder if it's not empty and it contain a valid path, or execute a method if an another field is not empty.

I'm looking for a trigger/event for execute a method for do that but i didn't find anything.

The relationship type/grid event has only the onInsertRow, onSelectRow or on DeleteRow events.

Someone can give me an advice on how i can execute a method when the relationship grid, or single row of relationship grid, is loaded?

Thank You