DataMapper ORM v1.8.2

[eluser]maikens[/eluser]
Hi, I have the following scenario:

There are are three tables involved in this: groups, user_types, and resources.

user_types have a many-to-many relationship with groups - The user can create user_types, say one named 'painter' and one named 'foreman'. They can then choose which user_types are available to each group. For instance, assuming there are two groups 'a' and 'b', the user might decide that group 'a' has painters and foremen, and that group 'b' has only painters.

So when creating a resource, such as a manual, the user specifies which user_types can access them in each group. So the user might create manuals 1 and 2, and assign manual 1 to painters in group a, and manual 2 to painters in group b

My tentative DataMapper solution to this is to have a many-to-many relationship between groups and user_types using a join table called groups_user_types. Then, that join table has a many-to-many relationship to resources, using a join table called groups_user_types_resources. I am unsure if this can be done in DM, as I can't find any documentation / examples with this particular relationship. Can I do this in DM, and if so, how? And if not, any suggestions on how to implement a solution blending DM with CodeIgniter's Active Record class as painlessly as possible?

Db tables would look like this:

Code:

resources
---------
id|name
1|manual1
2|manual2

user_types
----------
id|name
1|painters
2|foremen

groups
------
id|name
1|a
2|b

groups_user_types
-----------------
id|group_id|user_type_id
1|       1|           1
2|       1|           2
3|       2|           1

groups_user_types_resources
---------------------------
id|resource_id|groups_user_type_id
1|          1|                  1
2|          1|                  3
3|          2|                  1
4|          2|                  2

I'd appreciate any corrections and insight you could provide.