Hi @rj008 ,
As far as I know it is not possible to do it via gmail plug in. You may check out this tool in market place: https://ecosystem.hubspot.com/marketplace/apps/marketing/data-management/liyfe-1061429, it works like google sheet or airtanle, you can add multiple products to deal line-items on spreadsheet cell and it syncs with your HubSpot at real time. Good way to save time
Hope it works
SC