Because hydraulic systems are applied to such a wide range of different machines, industries and applications a user might prefer a bespoke course tailored to their needs. In this case it is worth approaching one of the large training establishments listed above and asking them to develop a machine-specific course.
Alternatively, search for a specialist company via your local trade association. Such companies often design, maintain or build hydraulic machinery for their customers and offer bespoke training as an add-on. An example of this is Bachy Soletanche ( http://www.bacsol.co.uk/ ) in the UK who are a leading geotechnical specialist within the field of foundation and underground engineering. They operate a large fleet of drilling and boring machines made by many different manufacturers. Their training courses reflect the specific knowledge needed to maintain the hydraulic equipment on these machines.
In the USA, companies such as GPM Hydraulic Consulting Inc. (https://gpmhydraulic.com/) also supply a range of standard and bespoke training courses as well as providing troubleshooting and reliability consulting services.