shortcut for new Messages with selection

Dear Apple Community,

I would like to be able to select an item on my desktop and type a shortcut to attach the selected item to a new message with the Messages app. I've tried to create one in system preferences/keyboard/keyboard shortcuts/Application Shortcuts under Finder.app typed "Share>Message" and it didn't work. I have a shortcut to "new email with selection" that I created with automator but Messages is not an option there. I also tried searching for an Applescript or terminal command for this so I could do it with a swipe gesture using Better Touch Tool. I spoke with an Apple senior advisor and he said he didn't know how to do it either and to post it on the forums.

If anyone knows how to make a shortcut for this action, please let me know.