Maintenance intervals

I have been commissioned, in order to achieve more active maintenance of my company's vehicles, try to organize this in an effective way. No matter how much I have searched online, vehicle manuals etc. The distribution change periods, and I have not found anything.
Can anyone tell me that distribution strap intervals do these vehicles have?
Renault Master 2.5d 80 hp year 2001
Fiat folded 1.3 75cv (diesel) year 2007
fiat scudo 1.9 (diesel) year 2007
I think that the Renault Master is the Sofim S9u engine, folded it I think it carries chain (unconfirmed) and the scudo I think it carries PSA engine