Create a new Gmail account. Then create a rule in Outlook to redirect emails containing the pager code to the new Gmail account. If you are on ActiveSync, then your Outlook is presumably connected to an Exchange server, and the rule will be stored to the server (meaning you don't have to leave Outlook connected for it to work). Finally, add the Gmail account to your Android phone (you can have up to five I believe), and within Gmail on your phone assign this account special ringtone.
There may be a way to do this with an just an app, but this is the way I would do it. Good luck!