Keyboard connection preferences

Hi there, does anybody know if there's a way to, using the keyboard, select which device you want it to connect to? I mean if there's a way to program something like 'car-stereo presets' in the keyboard so, when you press a combination of keys, the keyboard chooses to connect to a specific device, if the combination of keys is different, the keyboard to choose to connect to a different device.

I like the idea to have only one keyboard and be able to EASILY make it connect to my iMac, to my iPhone, and soon, so it seems, to my Apple TV, just by pressing something like the on/off button + 1, or on/off button + 2, or on/off button + 3. Something like that.

Thanks in advance!