Ugh, that's a terrible problem to have.  I'm not being sarcastic either, these things are a huge mess and having to pour five of them into one pot and stir would have me pulling my hair out!

I'm not a Lacertian, but I would combine the refi and the bank that bought it into one entry.  When these things get sold the only difference is who you write the check to, the loan is still on the same amortization schedule.  So, in essence, pretend you paid the original refi bank whatever's on their 1098 PLUS whatever's on the acquiring bank's 1098.

There is sometimes an element of finesse with these things.  Certain "monthly average" methods are not available in all circumstances.  I'd encourage you to have an expectation of what the answer is before entering everything into the software so if it's way out of whack you can look back at your data entry.  Pub 936 has some info:

https://www.irs.gov/pub/irs-pdf/p936.pdf

Page 13 (2019) lists different methods that can be used to determine the monthly average and also has the "You can use this method if" criteria listed.  It also tells you what to do if you have mixed-use mortgages.

Good luck!

Rick

PS: Someone from the Lacerte side could come along and tell you how to get a 5th column in there, if so you should ignore me and listen to them!