What is the general procedure for overriding a key binding set by a package?

I have a global key binding for a function I wrote (using "global-set-key").  I recently started using "groovy-mode", but I noticed that this mode is using my key to bind to something else.

What should I add in my "groovy-mode-hook" to make it use my global binding instead?  Or is there a "more correct" way to do this?