@ВeekeeCZ wrote:
Then just save a layer state of xref's layers and apply that in new drawing. Not sure where is the issue.
At Layer State Manager, use the Edit option and remove all other layers from layer state than your xref's.
Thanks for the good suggestion. For some reason, I was unaware that you could save a layer state that applied only to a certain subset of layers within your drawing. Using this advice, I was able to easily go to the first host drawing, create a layer state of only the layers from the target xref, export the .las file, open the second host drawing, import the .las file, and restore the layer state that affected only the target xref.
One minor point that others should be aware of is that you should uncheck the box "Turn off layers not found in layer state" before importing the layer state, so you can restore it right away without turning off layers you still want.