MeshDeform on multiple objects ?

I’ve one object made of a few pieces, when shift+select them all and them apply MeshDeform to them it works only with first selected objected.
Is there any way to make it work with all selected objects ?

Join all meshes into one single object.
Select them all and press Ctrl+J.
Last step is to add the Meshdeform modifier to the single mesh.

If you wanna select pieces inside your mesh, enter edit mode and select a vertex, if you press L it will automatically select all the other vertices attached to the same piece.