Twilio inbound voice / sms with autoresponder

We are currently using a shared VOIP account to manage a call-in / text line for health information. The line is covered 9-9 Eastern by our staff and a team of volunteers (one-two online at any time). Ideally, volunteers would be able to use an app/site on smart phones and staff would be able to use either smart phones or a web app on their desktop (mostly Windows). I'm currently seeking quotes from our phone provider for their call center offering, but would like to know if it's realistic to have someone build a Twilio app for this.