Bonjour tonyastro,
What you're looking for is a classical subd tool, aren't you?
Unfortunately, in Softimage 3D there is no such tool. But you can do it anyway if you have the Pheonix Tools, a set of great plug-ins, wich has this kind of function.
On a side note, you can easily do it, without any plug-in, if you use patch and nurbs objects.... I can tell you how if you wish so.
Sorry for bringing the bad news.
Salutations - Cheers
Bernard Lebel