What I would do is write a flag to your local storage that says, in effect, " root/myurl is the last URL I visited." And when when someone reloads "root/myurl", check to see if that flag exists. If it does, renavigate to "root/". It s a little complex, but something of that sort ought to work.
The other approach I usually take in these instances, where I find myself wanting behavior that doesn t match how the browser normally behaves, is to figure out why I m doing things different from everyone else. Quite often (almost always), there s a better and more natural way to do it, if I ll just take a step back and figure out what I m really wanting.