How to detect Listing/Details view of a dynamic content from

Hi,

Let's take an example that I have a dynamic module called "Press Release". In my page "Press", I put in a "Press Release" widget and a custom "RHS block" widget and set the "Press Release" widget to display both listing and details view on the same page.

Thus, when I browse http://mysite.com/press and mysite.com/.../new-cat-in-your-block, they are pointing to the same page. How do I detect the difference in my "RHS Block" widget to let it display different information based on the selected article?

Thanks,

Harry