Weblogin and Multiple User Groups

Hi,

Im working on a site with user registration, however i understand the basics of single landing pages but what i need is multiple landing pages.

for example we have 3 users(A, B and C.) And 3 User Groups (D, E and F)

User A belongs to User Group D
B > E
C > F

So, User A visits and Logs in, they get redirected to document id 10.
User B, logs in and hey get redirected to document id 20
User C, logs in and hey get redirected to document id 30

They all have different landing pages.

at present i understand how to do it for 1 user group, but i have no idea how to make it for multiple

Anyone any ideas please

assign to each page of a different landing different template
each template assign to a different web users group

sorted thanks