public ExcpM(string Msg, StackFrame parCallStack = null, bool show = true)
{
    StackFrame LcallStack;
    if (parCallStack == null)
       LcallStack= new StackFrame(1, true);
    else LcallStack= parCallStack;

        //do stuff with info in LcallStack ..
}

public ExcpM(string Msg, StackFrame parCallStack = null, bool show = true)
{
    StackFrame LcallStack;
    if (parCallStack == null)
       LcallStack= new StackFrame(1, true);
    else LcallStack= parCallStack;

        //do stuff with info in LcallStack ..
}

public class ExcpFlsV:ExcpM
{
    bool Rtrn { get { return false; } }
    public ExcpFlsV(string bsMsg, StackFrame bsCallStack = null)
      : base(bsMsg, bsCallStack)
    {

    }
}

public boolMethodReturn()
{
    //unless adding Local callStack field to every method passes ctor of ExcpFlsV as calling method
    StackFrame LcallStack = new System.Diagnostics.StackFrame(1, true);
    if(some condition no met)
      return new ExcpFlsV("some error message...", LcallStack).Rtrn;
}