You cannot tell the browser to ignore the security instructions provided by the third party site. That would defeat the object of having them in the first place.
If you want to display the content on your site, then you will have to display it from your own server (e.g. by using a server side process to read the data from the third party site and serve it from your own). Obviously, this will mean that you cannot (for example) load Facebook using the user's own credentials.