Multiple FEIN entities for W2s

 I know - I'm crazy for thinking of W2s in September. But we have been doing W2s for a single FEIN for years and feel pretty comfortable with the process. However this year, we will now have to process W2s for two additional entities. Are there any tips, tricks, lessons learned for processing W2s for multiple entities? I would like to work out any major blips now before we are in the crunch time of actually doing the W2s. I have been playing with these in our test system and have removed the "Company # of Reporting Agent" from the