Accesing to all virtual interfaces

Hello Guys,thanks for seeing.I have a problem with my Router,the question is that i have mi router connected to a WI-FI that has a captive portal,and i have created 7 virtual interfaces,so,every user can log into this captive portal independently.So,my question is,i’m the admin,how can i have access to all virtual interfaces simultaneously?I mean,i make a request to Facebook as an example,so,there are a user logged in a virtual interface,how can i have access to internet through this interface??Thanks in advance guys!