Input account group in corresponding cell

[minjak]

These are income accounts from our system, and its only small part as you can see from row number. I need some function that will write name of the group in column A( that I decide ofcourse) that corresponding account from column B is in.
For example, for every 67900000 from B write Non production income in corresponding A cell.
Catch is that every first in the month Ill be pasting accounts from previous month so It would be nice that I can just fill the series in rows that I add.

Thanks!!!

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