How to use diffrent modes at same time on a phone for different callers For two different callers call on a phone, Is it possible that phone is on vibrate mode for one caller and on ring mode for different user?

My question is in terms of making an application. Is it possible for two different caller when they call at same time on an phone for one the phone is on vibrate mode and for other it will be on ringing mode. Like what i am thinking is to start a service that run in background, So when a call is coming from a particular number it will switch it to vibrate and for different no it will switch to vibrate.

But again the thing is service can listen only one number at the time. So the phone can either work on Vibrate or its in ring. Can it be possible that two mode run simultaneously for two different number?

IF so then hows it possible?
By default you can set different ringtones for each contact by hitting the menu button form the contact window and choosing options.  To add vibration into that mix you can use an app called WhoIsIt, that among other things lets you set different vibration patterns for each contact.  

Another way is suggested in this answer.

A more powerful but complicated way to get this done would be to set up different profiles for each caller in an app called Tasker.