Program suggesting an option based on previous queries?

I want to create a program that decides which option best suits a certain query based on previous queries and their respective suggestions proposed. Basically, 'training' the system to have an idea which suggestion most suits a question.

Example:

In this scenario patients input a Appointment number to see a doctor in a specific ward. Previous data is as follows:

Appointment Number: 257 Ward Directed to: 28

Appointment Number: 352 Ward Directed to: 10

Appointment Number: 546 Ward Directed to: 35

Appointment Number: 234 Ward Directed to: 28

As you can notice, the appointment numbers within the 200-300 range have been directed to the Ward 28. Here onward, the system will know that this range should be directed to the ward 28.

Since this is the analysis stage I'm in right now, What most effective method should I use to develop this system? Machine Learning? Statistics?