Groups are collection of ledgers of the same nature. Account groups are maintained to determine the hierarchy of Ledger Accounts, which is helpful in determining and presenting meaningful and compliant reports.
Tally.ERP 9 has the flexibility of setting user required chart of accounts. You can group the Ledger accounts under the required Groups at the time of creating the chart of accounts or you can alter them at any time.
The Group behavior is classified into Capital or Revenue and more specifically into Assets, Liabilities, Income and Expenditure. The Groups ascertain whether the same will affect Profit and Loss Account which is revenue in nature or Balance Sheet which is capital in nature.