How to implement items from other mods?

Okay, so I know it initially sounds far-fetched if not impossible to implement items from other mods into MCreator but, it has a fully fledged Java code editor so that could help. How would I call to the packages and resources from other mods to implement there features into my mod. I think there might have been a file somewhere in the install directory that included a file that addresses every item that MCreator has access too and maybe I could implement that item (based off of ID or class or something) and call to the class and then have the item implemented. Don't know if this has been tried before but, seems like it's should be technically possible.