IFS or anyother function

Dear Experts,

                    I have a data like below:-

So, Column "B" - sfn can go from 0 ~ 1023, and Column-"C", can go from 0~19, Column "G" has 3 values(rnti's) - 

Now, we have only 2 situations like below in Column"E", where I need the formula:-

Either all these 3 rnti's can be Multiplexed in the same sfn.slot So, in below snip all 3 rnti's are FDMed in same sfn.slot - 394.6 and should be continuous, so Column "E" should have fdm-3

But in below instance, in 395.2 we have only 2 rnti's multiplexed(so fdm-2 should be populated)

Attached is the spreadsheet.

Thanks in Advance,

Br,

Anupam