Article 18(5) provides a definition for where a person is appointed to help the responsible person undertake duties to undertake preventitive measures (anything identified by the RA as being required to safeguard relevant persons - such as training) 

18(5) A person is to be regarded as competent for the purposes of this article where he has sufficient training and experience or knowledge and other qualities to enable him properly to assist in undertaking the preventive and protective measures. 

Of course, it is for the responsible person to determine the level of competence required in your location (someone training staff in the use fire extinguishers at a fuel depot or theatre would have to have a greater level of understanding than another who is instructing a handful of staff in a corner shop)

A train the trainer course may be suitable, or if you have staff who are capable (and the risk of fire is low to moderate) why not get a trainer in to provide a one-off session to staff and get your would be trainer to make notes in order they can cascade their learning to others?

Its sort of train the trainer, but in a specific subject matter rather than a general TTT type course