As Scotty said - - Which certification?
Also, what does the external company actually do for you - management contract for instance or is it a co-packer?
We've had clients where the client paid for our services and we in turn helped their suppliers to get SQF certified with our direct client paying all costs, paying partially or requiring the suppliers to pay all costs.
It can actually get rather sticky when an external company has a lot of capital improvements that need to be made or needs to re-organize the make up of personnel in key positions or hire additional people for positions that current employees can not or will not handle.
My suggestion is that you make XYZ certification a requirement for "Y" and that they pay for all related costs (except consulting fees) with your company offering suggestions based on how your company became certified, what was involved, how you handled this and that.
In this mode, your company provides a referral for a consultant to help "Y" and either pays for consulting fees and auditing fees (first year) or provides a direct amount to company Y towards those services.
All the Best,
All Rights Reserved,
Without Prejudice,
Glenn Oster.
Glenn Oster Consulting, LLC
Consultants for SQF, ISO-certified payment systems, Non-GMO, BRC, IFS, Lodging, F&B
http://www.GlennOster.com -- 774.563.6161