add/remove TraceListener to all TraceSources

I am looking for a way to add and remove a TraceListener for all existing TraceSources.

(I am not sure my approach is correct here, what other ways could I use? Basically I want to log all trace output into a file that uses the current project name as filename. Whenever a user creates or reopens a project, I want to append logs to the correct file. There can only be one project open at a time.)

Code example:

I create several TraceSources in my application, one for each class

public class Class1
{
    private static readonly System.Diagnostics.TraceSource trace = 
            new System.Diagnostics.TraceSource("Class1");
}

public class Class2
{
    private static readonly System.Diagnostics.TraceSource trace = 
            new System.Diagnostics.TraceSource("Class2");
}

I now want to add or remove a traceListener to all my traceSources at Runtime, like this:

private System.Diagnostics.TextWriterTraceListener myListener;

private onProjectOpen()
{
    // user created a new project or opened an existing one
    myListener = new System.Diagnostics.TextWriterTraceListener("log-"+projectname+".log");
    ALL_TRACESOURCES.Add ( myListener) ; // <-- how to do this?
}

private onProjectClose()
{
    // user closed a project
    ALL_TRACESOURCES.Remove( myListener) ; // <-- how to do this?
    myListener.Flush();
    myListener.Close();
    myListener.Dispose(); // <-- not sure if all this is neccessary
}

So far I found no way to do this without making all my traceSources public (seems like a bad idea) and then listing all my classes like this:

Class1.Trace.Add( myListener );
Class2.Trace.Add( myListener );
...

which seems like a bad design choice on several levels.

Or

Add all my TraceSources to a custom global collection in the constructor of each class (Easy to forget / mess up; and global variables are bad )