battle order for multiple attacks on the same province during one turn ?

[Boron]

is there a rule for the battle order when multiple attacks on one province done by different nations all at the same turn happen ?
how works this rule then ?

or is the battle order chosen randomly ?

an example :

1. player A + player B attack the same indipendent province

the player first chosen has to fight both the indipendents and after this in an additional battle the other player .
so the first chosen has a disadvantage .

do player A and B both have a 50% chance of being the first attacker or will it always be player A ?

if my concern that it is not random is proven to be right i perhaps add a more complex example which could happen too (although very rarely )