Enhancement in existing web application (golang developer)

About Application:- A Dialer application which keeps the number engaged continuously when added to web site. Currently it is able to call only one user at a time. Skill Required : golang Duration : 3 days Functionality which needs to be added 1. Should allow to call multiple users /Mobile number (Maximum 5 numbers can be added.) 2. Should be able to send text to single and multiple users /Mobile number 3. Change text to voice. basically needs a text box that when submitted sends the text to google api to read and store the wav file which then is sent to the caller and played back. 4. Should be able to change text to voice to multiple as well as single users 5. All calls and text msgs to single or multiple users must have a configurable interval, for example you want to call after every 5 sec , 15 sec or 1 min.