Company and unit of company can both filed GSTR 9 AND 9C separate

I have one query

if company and there unit both are in different state,
GSTIN are different but pan are same

and there are only one final statutory audit balance sheet and income tax return.

Can company and unit of company required to filed GSTR 9 and 9C separately
or only one GSTR 9 and 9C

please provide information and there sec and rules and guidelines and
notification if any