Custom Caller ID based on Number Dialed Asterisk

We have a client that owns a couple flower shops throughout the country. The use Asterisk 1.4.25 at their headquarters. At the headquarters they have a small call center (4 agents) that follow up calls makes calls on behalf of their remote stores. They want to their phone system to change the Outbound Caller ID based on what phone number the call center agent dials, if that number exists in their customer database. Here's an example Agent = Jane Smith, Exten = 100, Default Outbound Caller ID = 310-555-1212 Customer1 = Joe King, Phone Number 661-555-1212, Local Store Phone Number = 661-888-1212 Customer2 = Diane Wallace, Phone Number 212-555-1212, Local Store Phone Number = 212-888-1212 Jane Calls a Joe King Asterisk looks to see if Joe's number is in the customer Database If it is, then Jane's caller ID is changed to 661-888-1212 If not then Jane's caller ID stays 310-555-1212 Jane Calls Diane Wallace Asterisk looks to see if Diane's number is in the customer Database If it is, then Jane's caller ID is changed to 212-888-1212 If not then Jane's caller ID stays 310-555-1212 We can run a dump from the customer database to create a csv file that has Customer phone number, Store Phone number. We'll update the csv file nightly. But it will always be in the exact same location on the asterisk server and the format will never change.