Map a single material across multiple objects or faces
Join all objects with Join tool.
Note, you can only Texture Map one object at a time so joining the objects makes them one object.
Select joined object or faces of the same joined object with Pick tool. Reminder: hold Cmd + Shift (Mac) or Ctrl + Shift (Win) to select multiple faces.
Select desired material in Materials Palette, select Paint tool, click a blank area, and observe the material is applied to the selected item(s).
With the item(s) still highlighted select Map Texture tool, in Tool Options choose Mapping Type: Flat, click a blank area, and observe the material is mapped across selected item(s) as one mapping system.
Select Edit Texture tool, click on any face, then drag controls to position and scale material as desired. To tile the image one time simply drag/snap yellow dot to lower left corner then drag/snap horizontal and vertical arrows to the other corners. If needed use Edit in 3D option in Tool Options to further adjust texture mapping.
An alternate method can be used if you want to map across multiple objects without joining them as follows:
Use Paint, Map Texture, and Edit Texture tool on one of the objects. Adjust the texture mapping size across all other objects as in the previous example but you won’t see the effect on the other objects until the next step.
Use Copy Attributes tool to copy the Material and Texture Map Control attributes to all the other objects.
Note, this method copies the same texture mapping origin and size to all the other objects and the only limitation is you have to Copy Attributes again to all the other objects everytime you make a texture mapping change.