Hello Mohit,
Underneath Administrative or General are you going to assign GL codes??
If so, please create a set in transaction code GS01 referring table SKA1 and field as SAKNR. Set type should be basic set.
Select Hierarchical maintenance and then create your own hierarchy. Save it.
Assign this set in GRR1 Characteristics Account number. On the explode parameter, select explode.
Now you should be able to see the headings and then the GL code.
Best Regards,
Raj