In my grails application I'm using spring security plugin to handle authentication using email and password of a user.
Now I need to integrate my application with an external system which works on membership number and password.
In 2nd scenario I want to authenticate user by asking them their membership number and password call an external web-service fetch their information like email and authenticate them in my current application.
So effectively user can either use directly their email address and password combination or membership number and password combination to authenticate them selves.
Any suggestion how I can achieve this ... thanks in advance :-)