Updating a TM with different “type” (flavour) of language

I worked on a project with 2 TMs, one English (US) ->Spanish (US), and the other English (US)->Spanish (Spain). The project came as a package from the client, which was in English (US) ->Spanish (US). The second TM, the English (US)->Spanish (Spain), did not get updated at all, even though I had the “Update” checkbox selected. Is there any way to automatically update the TM that didn't get updated (short of using WinAlign, or going segment by segment in the bilingual file)?