Are you looking for a specific ordering like 000-111-2222 ? If that's the case you might want to try a masked text box. There is a current thread in C# on this (http://www.daniweb.com/forums/post1440491.html#post1440491) (I know it's not the right language, but it's the same .NET library, so you'd just have to translate it into C++ syntax).
If that's not what you need, post back and we can help you figure out what you need.
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...