Apparently, it is.
From Brewtarget.org
"It also can export and import recipes in BeerXML, allowing you to easily share recipes with friends who use BeerSmith or other programs."
In Brewtarget, the Export Recipe button is how it operates.
On BeerSmith's end, I would think File > Open File would be the correct way to open the recipe. Then you can just copy/paste the recipe into the desired My Recipes folder.
I'm not sure if you have to do this just one recipe at a time, or if you can import in stacks. The latter would be a lot more convenient. Since both are using Beer XML, I would think you could.