Migrating group companies from Tally 7.2 to Tally.ERP 9 will require you to individually migrate the companies and recreate the group.
To migrate group companies
Migrate each company individually from Tally 7.2 to Tally.ERP 9.
After migrating the companies, re-create the group company in Tally.ERP 9.
'Migrating Group Companies' has been shared with