4
It will definetely be a good idea then to integrate it. You can make the WISP section as a module. You can use the functions in XOOPS to handle the authentication at the same time. For example you can create a user group called 'wisp', which you give the right to add pages and then based on the userID and authentification check edit their own pages.
I think you will be able to find enough support from the XOOPS community when you need help with the integration.
It will take you some investment of time but the result will be rewarding when you finished.
Martijn