Hermetic Sanctuary?

By the time I got the tech to build the Hermetic Sanctuary the Ice God faction had already built it. I've only just started to conquer their territory and much to my surprise I found it built in a city closest to my lands, the old Dervellio (sp?) capital is to the South East. If I had raised the city would I have then been able to build the HS myself? And is there any way one can get the tech and build it before the enemy does?

The same wonder rules apply to FFH as in normal Civ, so if you destroy the wonder, its gone forever.