Writing application or site collection specific layout page

Scenario:
I am sure this is very common. Often more than one project is customizing sharepoint and they want to restrict their custom layout pages to their particular site collection.

Solution:
I introduced a check in the page load and accordingly I display the page.

For SetApplicationNameFeatureReceiver.cs :
Read article How to update to property bag using feature.

Code( ApplicationPage.cs):

 public class ApplicationSpecificPage : LayoutsPageBase  {
    protected override void OnLoad(EventArgs e)   {
        try    {
            // Make sure not to include '/' at the end of URI
            string AppName = "MyCustomApplicationName"";

        if (AppName != null && SPContext.Current.Web.Properties["AppName"]!= AppName)
               SPUtility.TransferToErrorPage("Page does not exist.");

            if (!Page.IsPostBack) {
              // Do Something
            }
        }
        catch( Exception){
            throw;
        }
    }
}