Dynamic Control Bundles for ToolkitScriptManager?

Is it possible to have a ToolkitScriptManager on the master page of an application, but have each page specify which control bundle they need?  Something along the lines of:

<ajax:ToolkitScriptManager runat="server" ID="ToolkitScriptManager1" />

then in a code behind:

ControlBundle myPageBundle = new ControlBundle("myBundleName");
ToolkitScriptManager1.ControlBundles.Add(myPageBundle);

I've been reviewing the toolkit code and it doesn't look like this is possible in the current version.  Can anyone confirm this?