in the example , there writes:

[queues]
finland = /var/spool/sms/finland
other = /var/spool/sms/other

[providers]
finland = 358, s
other = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

If I use queues of finland and prefix of the destination phone is not 358,

what would happen? massage can't be send ?

If you define Queue: finland in the SMS file, it will override automatic sorting.