Call another plugin from my plugin

Hi, I want to make a plugin that automatically converts my .epub to .kepub format when it's imported. Currently there is a plugin that makes that conversion, what I want is to call it whenever the user imports a new epub, then call another plugin that counts the pages, and then another plugin that hyphenates the words on it.

How can I call a plugin from my own FileTypePlugin?

Thank you very much :)