Hello,
Import your block and change its layer, repeat for different layers.
See:-
http://wiki.librecad.org/index.php/LayersChanging an Object's Layer
Sometimes it is necessary to change an object's layer. This describes how to move one or more objects between layers.
From the menu select Modify->Attributes
Select the objects you want to change the layer of. See Selections for a detailed description of how to select objects
Select the continue action button (double right arrow)
In the Attributes dialog, drop down the Layer selection box and choose the desired layer.
Alternatively you can activate the option Application Preferences → Defaults → Modify layer of selected entities, at layer activation
With this option enabled you can move objects to a layer by selecting the objects and then selecting the destination layer.
Regards
strikeeagleIII wrote
Is it possible to have an object like a block belong to multiple layers? i.e. I'm drawing the electrical wiring for my home and it would be nice if I could assign blocks to belong to either the upstairs or downstairs layer, and also to the layer of the respective circuit breaker they are on. Is that possible?