Role resolution for "monetary approver": help needed...

[Hassine, Felix]

Hi all,
 
I have a (complex ?) role to build, and I have much difficulty. I would
appreciate if you have any idea to help me out from this problem.
 
I am trying to buid a role for a monetary approver. This is defined as this:
 
        - Input: an agent , who has already done something in the WF.
        - An invoice document amount
 
        - Output: a list of agents who :
                1- belong to the same org. unit as the input agent or in
higher org units
                2- who are able to approve the given amount.
 
I have tried the following: create an evaluation path to get all the orgs
where the input user belongs and higher. It worked, and I have incorporated
this in a FM role, which returns all the organization units the input user
is in and higher. Create a second role based on a responsibility with the
amount as container, and make responsibilities for each amount range. Then I
have tried to combine both by putting the first role as "possible users" in
the task, and the second one in the step definition.
It does not work, because... I cannot put a role in the "possible agents".
In fact, I would like to make an "intersection" of the 2 roles.
 
I cannot hard code the amounts in a FM and combine it with the previous FM,
because the amounts ranges may change every day, and they must be maintained
by non worklfow experts.
 
If any one has had to "intersect" 2 or more roles, I would really appreciate
to understand how. I thank you in advance for any help.
 
Best regards,
 
Felix Hassine