In Zoiper for Android you can choose specific contact source on your phone.
For example this could be a specific Google account, Viber, Telegram, or something else.
With Zoiper 5 you can also add a google contacts as contact source, so you can use one Google account from which you manage your contacts and they will be available on all your devices. However, keep in mind that from Zoiper5, you cannot edit or create new contacts into external contact source.
