Nicole,
Best way to do this would probably be to create conditional logic on your form processing steps that sends an alert to only whomever the user selects. You would call the form field like this: If form field = Bob, send alert to Bob@company.com, If form field = Carrie, send alert to Carrie@company.com, etc.
Here is an article that might help:
https://community.marketo.com/MarketoArticle?id=kA050000000Kyu0CAC