I have my iPhone 5s paired to my car's bluetooth hands free system.
Receive Multiple Files Via Bluetooth
When the Bluetooth fails to transfer iPhone files to Mac, or causes missing some data during transferring process, you need to look for an alternative solution like using dr.fone - Backup&Restore (iOS) to facilitate the iPhone transfer. This phone transfer tool allows you to transfer iPhone (iPhone 8 and iPhone 7 supported) files to Mac or Windows PC with 100% original quality and without losing. On your Mac, choose Apple menu System Preferences, then click Bluetooth. Select the device in the list, then click Connect. If asked, click Accept (or enter a series of numbers, then press Enter). You need to connect your Mac with the device only once.
With iOS 9 I was able to sync only certain groups from the iPhone Contacts. This was useful as I have a number of groups in iPhone Contacts, including one specifically created for syncing to my car.
Bluetooth Mac Address
Since upgrading my iPhone to iOS 10, I only have the option in the iPhone's bluetooth settings to tick any combination of 'Phone Favorites', 'Phone Recents' or 'All Contacts'. None of these are useful for me as I want to sync with one of the original groups in Contacts.
Can't Receive Files Via Bluetooth