[HMM I OFF TOURNAMENT] "Company"

Is it allowed to do this?

No, it's not allowed... you might change the save file structure. :D :D :D
On any version of Heroes 1, the save file with the extension *.CGM can be read... just load it not as "load game"/"scenario", but as load/campaign...
P.S. In short, the name indicates that this is a campaign tournament... i.e., we play the campaign from a fixed save file. ;)