Can 401K and Catchup dbas use a table code to determine what the max should be depending on age

We are working to revise our 401K and Catchup dbas. Currently they both have different max's. The site would like to combine all of 401K and Catchup and use a method to decide whether or not the max should be 27,000 if 50 or over or 20000 if less than 50.

Is there anyhelp out there to set this up or has anyone done it?

Thanks in advance

Terri