Why would you want to duplicate an event like that? You can make use of the categories themselves and $showCat to acheive that exact thing and having to enter only a single event...
Create a category called "All Categories" (or whatever you want to name it), and assign your events to that one. Now, I'm assuming you are already using $showCat to have different pages display different categories... so all you have to do is modify what you're passing to $showCat to also include the new category you just created.
So now, instead of having for example $showCat="2" (showing only one category), you'll have $showCat="2|5" (showing the original category, and the "All Categories" category). Just add the |5 bit to all of your pages so that they all show the new category.
Now, you'll need to figure out what your category number is going to be, because it probably won't be 5, but you can find that the same way that you found what your other categories were. It should be just that easy.
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