Every section in the Groups represents an account that you have created. This is regulated in the main Settings of your iPhone, where you can predefine the accounts that you want to use – for example: iCloud, My Device, Hotmail, Google, etc. All changes that you make in the main iPhone Settings (e.g. create a new account, delete an account, etc.) will affect ContactsTap as well.
ContactsTap treats each account as a separate entity, and the main Groups window clearly displays this.
In ContactsTap, you can create as many groups as you like within each account. However, these groups will be independent from the groups created within a different account. Groups created for iCloud or My Device account will be treated as iPhone native groups and will be synced when devices is synced. Other acconts will not sync groups created for them trough the ContactsTap as iPhone OS does not allow native groups to be created on other accounts except iCloud or My Device. They will be treated as private groups to ContactsTap only. This is due to limitation of the iPhone OS.