How to hide a subclass from Activator.CreateInstance [duplicate]

This question already has an answer here:

• Hiding types from being listed in Assembly.GetTypes in .net 3 answers

I have some code like this

class outer : Plugin
{
   private class inner
   {
       //
   }
}

//somewhere out of my control
 foreach(var a in _plugins)
 {
    foreach(var t in a.GetTypes())
    {
        if(!t.IsClass || t.IsAbstract) continue;
        if(!typeof(T).IsAssignableFrom(t)) continue;

        T i;
        try {i=(T)Activator.CreateInstance(t, constructorArgs);}
        //..

In this scenario the activator creates an instance of my internal class inner. Is there a way to prohibit that, by 'hiding' the inner class somehow?