12. How many devices can be connected to a Bluetooth device simultaneously?
The official Bluetooth specifications state seven is the maximum number of Bluetooth devices that can be connected at once. However, three to four devices is a practical limit, depending on the types of devices and profiles are used. Some devices require more Bluetooth data, so they are more demanding than other devices. Data-intensive devices may reduce the total number of devices that can be active at the same time. If a Bluetooth device becomes slow to connect or does not perform reliably, reduce the total number of connected devices.
http://support.apple.com/kb/ht3887
