Yes... Let's say you have a page called index2.php you can put this code in it, in the same root folder where index.php is (please note I do not use wordpress)
<?php
require('index.php');
?>
Once you have done that, test to see if you can access the website as you usually would. If that works... then inside your wordpress files, look for this line of code... (I looked at the source code of this website to make the line of code below)
<link href="http://s.wordpress.org/style/style.css" type="text/css" rel="stylesheet" />
Now... that is the link to the external spreadsheet... So where ever it is inside your wordpress files you should be able to do somthing like this.
if($_SERVER['PHP_SELF'] == 'index.php'){
echo '<link //----the rest of the code for the first spread sheet.
}else{
echo '<link //----the rest of the code for the second spread sheet.
}
This is a link to the php documentation on the server variable. This tells you the entire "State" of the application or the information which is currently held in the SERVER global variables.
Variables are just a fancy term for something that contains data. Keys and Data.
http://www.php.net/manual/en/reserved.variables.server.php
So try doing this as well... find the line of code that has the link to the external spreadsheet, and then, print this in the php code and see what the variables look like when you call it through the index.php file and then see what it looks like through the index2.php file.
// NOTE: I tried to put a pre-format tag here but the comments took it out so I am writing the greater than and less than html traingular brackets in square brackets instead...
print([pre]);
print_r($_SERVER['PHP_SELF']);
print([\pre]);
That way you can get the right filename and path for use with the if/else switch which decides which html line to print.
Is this making sense to you? I am subscribed and pretty much taking easy today so let me know if I can help.
I am not a wordpress, so there is always a possibility that there are many other different ways to do this.