In my case, I could remove configuration of some companies and delete some company's data because all customers of that companies could be excepted.
But if some account group should be excepted and others are not, it looks so hard.
Daily customer specific transfer would be work, but your one account group will make garbage data into FDM_COLL_TROBJ everyday more and more if its company was initial loarded.
In my case, remove configuration of some companies and delete useless company data with Basis because used/not used customers are not mixed in one company.
No good idea now because your company has used/not used customers together and I don't know standard way to except some customers from writing trigger table but these functions are used for writing trigger table and you can get a idea of any modification.
Function FDM_COLL_WRITE_CHANGE_QUEUE - when posting
Function FDM_COLL_00001321_WRITE_TROBJ - when changing customer master