Dynamic access filter using embbeded yellowfin (iframe)

We have the following scenario:

• On our system we have an abstraction of a customer. We use customers as tenants, so each customer has it's own data and users.
• A user belongs to a customer, however may access (when allowed to) another customers.
• On your tables and the ones are available for yellowfin we have a customer_id field, we use to filter data of that customer.
• We can configure an access filter that will map a user to a customer.
• When the user uses yellowfin embbeded on our application, we apply an access filter to a report and yellowfin filters the correct data.

The problem is: when a user accesses another customer, as the yellowfin's access filter is not dynamic, we cannot for that specific session, the new customer_id value.

We're using the login-tokens rest api to generate the token and send to the yellowfin iframe.

As an example:

• Customer A is a consulting agency. Customer A has it's own customers. Let's name them Customer Y and Customer Z
• On our systems we have 3 customer_ids: "CustomerA", CustomerY" and "CustomerZ". Each one have it's own data.
• User Joe belongs to Customer A, however is allowed to access data from both Customer Y and Customer Z. On our systems, we already solve this problem, so if Joe click a buttom "Access Customer Y", all operations he does affects and reads data from Customer Y
• However, when Joe accesses the yellowfin embbeded frame on our application, as it's relation on the access filter is of Customer A, he cannot see data of Customer Y.

Important: we cannot use client organizations for this as:

a) on client organizations users are already segregated

b) we're already using client organization to map another abstraction on our systems (business partners/resellers).

How can we solve this?