When calling company, Ext. 10 is the receptionist phone and the only phone that rings. What needs to happen is, if Ext. 10 is not there, then I need the phone to ring to Ext. 11, if no answer then go to Ext. 24, if no answer, go to Ext. 13 which is the only ext. with voicemail. There needs to be some way that the phone rings at least 3-4 times before it goes to other extension. How can I make this happen?