We need to know how to set up the following:

1. Whenever someone calls our main number during office hours; they will immediately receive a message to press number (1) to speak with a representative; in which our phone number will immediately ring and we can answer the phone. (We have been receiving quite a few robo calls from the same company in which they use different phone numbers each time and we are trying to eliminate this problem).
2. Would this affect our current answering system that we have set up in which they would receive a voicemail message during office hours if the phone is busy; or if we have not answered after 5 rings?