Standard SMS rewrite
To quickly answer your question:
Is is special SMS in our case, as it comes from specific "Person" called "Kto tam?" meaning "Who's that". It says "Nieodebrane polaczenia:" ("Unanswered calls") and the number and date/time follows.
What I would expect is, it should behave exactly the same way as DR notifications work - no grouping, just lookup of any number in such SMS in Contacts and rewriting of number into more elaborate text based on rules just like in case of DRs. The only difference is, in such SMS there might be more than one number, which is not the case with DRs I suppose.
I do not know, if more users will appear, as I don't know, if there are many Polish Era subscribers on this forum or if such service is available for other networks (I would suppose so), but I can promise, I will make the solution known to my friends.
If this is not too much to ask for, I would be more than happy to test is. I suppose, adding such an option to DR notifier should not be hard (please correct me if I am wrong).
Best regards,
Kotek