Use the Bkper add-on for Google Sheets to quickly manage groups. It's a direct way to import or export existing groups between Bkper and Google Sheets. With this solution you can easily create groups in batch.
Import groups from Sheets to Bkper (Record)
On your computer, open a Google spreadsheet.
Click Add-ons > Bkper > Open.
Select your book.
Click Record tab.
Choose Groups.
Highlight the cells you want to import data.
Click Record button.
That's it! Now, the groups appear on your book.
Export groups from Bkper to Sheets (Fetch)
On your computer, open a Google spreadsheet.
Click Add-ons > Bkper > Open.
Select your book.
Click Fetch tab.
Choose Groups.
Select the cell you want.
Click Fetch button.
That's it! Now the Name, Type, Parent, (number of) Children and (number of) Accounts of your groups appear on Sheets.