使用SQL2008 Spatial函数，如何生成包含聚合结果的多边形

I've got a table of points, each with a name, latitude, longitude, and an area code. What I'd like to do is perform an aggregation (i.e. a "group by" clause) and return a polygon containing all the points for a particular area code. I've got a table of points, each with a name, l