This question seems to have the answer to your question: https://answers.atlassian.com/questions/74297.
Particularly, one answer gives this link: https://confluence.atlassian.com/display/CONFKB/How+to+Force+Links+to+Open+in+a+New+Window, which worked for me. However, where it says to go to 'Administration >> Custom HTML', it is actually 'cog icon >> General Configuration >> Custom HTML', under 'Look and Feel'. It will apply to every page in every space, but you can probably apply to a single space if you can find 'Custom HTML' in its configuration page.
Hey Everyone! Unfortunately, the venue that was hosting us on the 23rd has pulled out so we're looking for a new venue. If anyone would have a room free that we could use on the ev...
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