Open Browser Window

["DWDG" <webforumsuser@xxxxxxxxxxxxxx>]

I put this on the General DW forum but it occurs to me that was not the right 
place for it.  I think I over complicated the question as well!

 I am very much an amateur so need some help please. I want to have the 
facility on the intranet I run at work to occasionally open a browser window, 
on load, to display an important announcement. I can work out how to do that 
easily enough, and I will be giving someone else the ability to edit the window 
to open. What I want to avoid is having to activate a Behaviour to load his 
page whenever he needs it to appear when Staff logon the next day.

 My question is - is there a way I can set a behaviour that says "load this 
page if it is in the folder, but if the folder is empty, just load the 
intranet's homepage as normal, without giving a page not found message for the 
missing message page"

 Thanks

 Dave