Supplier Profile DFF - how to perform calculation in a custom DFF based on another custom DFF

Requirement:

There are two new DFFs configured 'DOB' and 'Age' under supplier profile. Whenever user enters the date of birth in the DOB field Age should be calculated and displayed in the Age DFF.

Please guide how to Achieve this without OIC intervention if possible.

We tried customization for this requirement at below levels. Still we couldn't achieve this.

1. At Supplier DFF definition level - via value set - Bind variable to pass the current context vendor id in where clause is not working
2. Using Sandbox Customization - Application Composer Groovy script- Supplier object is not available
3. Using Sandbox customization - Page composer for DFFs