How do I redirect the My Requests page to a custom page?

In our organization, users tend to have more than one account to login with (user, admin, domain, etc.). We created a custom My Requests page in the Portal that lets them see all requests submitted by any of their accounts. We would like that page to be the one that they get directed to after they submit a new request instead of the out of the box My Requests page. I have found what I believe is the correct js to use for this, but I am not sure where I need to apply that other than the customspace folder on the web server.

Any help is greatly appreciated!