i’m not familiar at all with nokia system, so i can’t help you more. The idea is that a MS which is only P-GSM cannot use a frequency “G1”, this is why mixing both bands within one MA list should not be done.
I wonder how nokia do it with BBH. I guess the G1 trx are hopping on G1 frq only, and PGSM are hopping on PGSM frequencies only. (?)