Spring security should do this automatically unless you have it turned off.
This will take the user to a url if they didnt specify one or if the setting is off after a successful login
grails.plugins.springsecurity.successHandler.defaultTargetUrl = ""
This setting you can simply not specify or set to false. This states that every time the user logs in they will be redirected to the default target url regardless of what page they attempted to access before they got the authorization request. So, if I understand you correct, set this to false or dont specify it at all and the functionality you want should work.
grails.plugins.springsecurity.successHandler.alwaysUseDefault=true