Write official statement to respond to the offensive content - Make the statement clear, doesn’t have to be totally formal, can be creative. But clear.
Post the statement on the hacked page disassociating with it, and requesting other XR groups to do the same. Request National page to do the same.
Comment on all hacked page’s comments with the statement Statement from your page, Report the account,try to disable the account under Twitter brand conditions
Check who has retweeted, and share the statement on all.
Engage any high-profile, energetic critics in conversation on the matter to some degree.
This spread the statement to their followers.