If I interpreted your question correctly, I would recommend that your company perform Due Diligence on the Resellers you have contracts with depending on how integral the Resellers are to your organization.
It is an important exercise for identifying risks that are presented to your organization. Resellers are a revenue generating function, which can carry high risk not traditionally critical by definition.
Beyond this, there is a customer impact at stake, which should be vetted in order to ensure security and availability of services.
However, I am not certain that the Resellers you are describing in the question are Critical to your organization. I recommend that you evaluate Criticality based on these 3 criteria as a best practice listed below:
- Would the sudden loss of this third party vendor cause a significant disruption to our business?
- Would the sudden loss impact our customers?
- If the vendor service is disrupted, would there be a negative impact on our operations if time to restore service required more than 24 hours?
Let me know if this helps and I would be interested in how others approach this situation!