How to set Dropdown List records that are not selected to be invisible or unabled?

I have an ASP.NET page to retrieve a country name from a list of calculations. Then I forward this country name to the next page which has a dropdown list ddlCompany loaded with a list of companies. Then I need to set one record in the list to be selected (the value passed from last page I mentioned above). Now since this page is read only, I want to disable (or set to invisible) all other country records in the dropdown list so that user only sees this record in the drop down list box. Or the dropdown list is diabled so that user can see only the record which matches the value passed from last page on the dropdown list text box area. Is this possible? Thanks a lot.