Hi Sreejith,

It is not very difficult.

You can use stAte option inside  -LAYER command to import Layer Staes (Layer groups) from another drawing.

Command: -LAYER
Current layer: "0"
Enter an option [?/Make/Set/New/Rename/ON/OFF/Color/Ltype/LWeight/TRansparency/MATerial/Plot/Freeze/Thaw/LOck/Unlock/stAte/Description/rEconcile/Xref]: A
Enter an option [?/Save/Restore/Edit/Name/Delete/Import/EXport]: I
Enter file name to import <Drawing2>: ~
Enter layer state names to import or [?] <*>:
Enter an option [?/Save/Restore/Edit/Name/Delete/Import/EXport]:
Enter an option [?/Make/Set/New/Rename/ON/OFF/Color/Ltype/LWeight/TRansparency/MATerial/Plot/Freeze/Thaw/LOck/Unlock/stAte/Description/rEconcile/Xref]:
Command:

When AutoCAD asks file name to import, you type ~ (Tilda) and hit Return to open window, where you can select drawing file with Layer states - you need to select .DWG file type from "File format" drop-down list:

after you select drawing, AutoCAD asks to specify Layer states names, just leave * option and hit Return three times to exit -LAYER command - all Layer states (Groups) will be imported along with descriptions.