You can give a simple example to make it clear.

You want to hide some classes within the namespace, isnt it?

It is called access modifier for class, it can also apply to method and property.

Available access modifier for VB.NET that I know:

public - accessible everywhere.

private - accessible only within the class

friend -  accessible within the class, namespace and the same assembly

protected - accessible within the class and any derived classes

protected friend - same as protected, but only within same assembly 

If this is what you mean, I guess this is the answer:

Namespace Logs.UI.WebControls

    ' Class that you want to make it visible everywhere
    Public Class LogControl

    End Class

    ' Class that you want to make it visible only in this assembly
    Friend Class LogControlDesigner

    End Class

End Namespace