Translation API with multiple dictionaries

I want to create a translation library containing multiple dictionaries. Each dictionary performs the translation from one language to another. There are multiple dictionaries available, but not all of them contain all desired entries. Therefore, to lookup a work from French to Italian for example, you might need to query French-English and then English-Italian. I need to design the translation library with a predefined number of dictionaries and create an API to perform a translation from a language to another using all the available dictionaries. How I can do this?