[Plugin: Contact Form 7] Action modification plugin possible?

I am in need of creating a plugin that would allow me to set a new action for the forms. I would also need to add 2 hidden fields per form that pull in data entered by the user.

By setting the action field I would no longer need the “To” and “From” fields. Could I suppress those if needed? Basically I’m asking if there is there a way to make a plugin that modifies the behavior of another plugin like this. And is that OK to do? Basically any user of my plugin would need to have Contact Form 7 installed in order for it to work.