Can you send parameters from a Job to a Pentaho MapReduce transform?

Let's say I have a transform that is written as a MapReduce task (as the Mapper in my case). From my Job that calls the transform via Pentaho MapReduce, I'd like to send a few parameters to the child transform so it can perform specific logic based on the parameter. This way, I can reuse the same transform for multiple purposes.

In the Pentaho MapReduce config dialog, I see a User Defined tab, but that appears to be for Hadoop-level parameters; not user-level parameters.

Any input would be appreciated.

Thanks.

-Barry