Choice/reference field that will show two fields on choosing choice/reference

[G Balaji]

Hi,

I'm defining a custom table extending from task table.

I've a field which will show the list of choices. Choices will be from another table. While I'm showing up the choices to the end-user, two fields on the reference table has to be shown to the end-user to choose one choice. 

Which data type should I choose to implement above requirement? Choice or reference? 

Is there anything called "lookup" data type? Wil that data type be suitable for this requirement? If so, how do I implement it because I dont' see it as a data type.

Thanks.

[puneetgoels1]

there is a field called dependent in sys_choice table that can be used as the other columns reference field