Logging and potentially blocking XHR Requests by javascript using selenium
browsermobproxy integrates easily and will allow you to capture all the requests made. It should also allow you to block certain calls from returning.
It does sound like you are scraping a site, so it might be worth parsing the data the XHR calls make and mimicking them.
I have some kind of single page application which composes XHR requests on-the-fly. It is used to implement pagination for a list of links I want to click on using selenium.
The page only provides a Goto next page link. When clicking the next page link a javascript function creates a XHR request and updates the page content.
Now when I click on one of the links in the list I get redirected to a new page (again through javascript with obfuscated request generation). Though this is exactly the behaviour I want, when going back to the previous page I have to start over from the beginning (i.e. starting at page 0 and click through to page n)
There are a few solutions which came to my mind:

block the second XHR request when clicking on the links in the list, store it and replay it later. This way I can skim through the pages but keep my links for replay later
Somehow 'inject' the first XHR request which does the pagination in order to save myself from clicking through all the pages again 

I was also trying out some simple proxies but https is causing troubles for me and was wondering if there is any simple solution I might have missed.