Employee service to sister concern

one employee working in X company and gets salary .He also work in Y company & gets some amount for other work regularly.Y company is a sister company of X. Both company directors are same but legal entity is different.
X company debited his payment as salary in books of accounts.

Y company debited his payment as miscellaneous expenses in books of accounts.

1 Can is it treated as supply from X
2 what is the GST impecat