Select options, options on search

Hi gurus

I recently created an ABAP Webdynpro application that contains select options on the selection screen. I followed this tutorial Using Select Options in WDA Application

The problem I have is that user must activate the options (EQ, BT etc) by pressing the yellw arrow and activating everything manually in the popup.

What I would like to do as I have seen in standard SAP webdynpro applications is that if the user enters only a single value in the low field and then presses on the Search button to set the option to EQ and if there are values in both low and high fields than automatically set the option to BT.

Thanks and regards,

Gunnar Má