Not able to compare the Input Rate values for populating value in another Rate Definition

Summary:

We have created one in rate defination and and that rate defination input value need to be compared with another rate definition.Hence,we are not able to do the configuration for this requirement as in Values Defined by Criteria there is no option to get the DBI for Rate Components

Content (required):

Here we have rate defination Called Basic Salary. We need to configure another rate definition values define by criteria where we can compare the input value of my original rate definition which is Basic Salary. Like if Basic Salary (original rate definition) is less than 21000 then employee will get budgetary releif allowance (another rate definition) of 1000 and Basic Salary is less than 42500 employee will get budgetary releif allowance of 1500 . Can we do this caparison on run time with Basic salary rate defination.