Employee Number to be generated in conformity with my Organization Format

Please how do I set my ERPNEXT system to be able to generate employee number as explained below:

In our Organization, below is what makes up an Employee Number;

  1. Year of Appointment
  2. Department Number
  3. File Number
  4. System Generated last 2-digit number

See the example below:

Name: John Francis
Year of Employment: 2014
Dept: Accounts (Dept No: 025)
File No: 109
ERP Generated ??

John’s Employment number should then be: 142509??
14 been last two digits of Year of Employment
25 been last two digits of Department Number
09 been last to digits of his file number
?? been the two digits (from 1 to 9) expected to be generated by ERPNEXT)

Please how do I replicate the above illustration on our ERPNEXT system?
NOTE: I have customized the Department form to include Department Number