Odd INDEX/MATCH

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I am having a bit of trouble trying to determine this index and match. My end goal is to automate this through VBA, but I will settle for just the formula. I am trying to INDEX the titles based on the subcodes. I have thought of doing a MATCH/LEN combination, or a HLOOKUP, LOOKUP and have tried

(I know that I don't have the xldown/up in yet)

                      For Each ce In Destination.Range("[Range is different then in example below]")                                   
                                     If Source.Cells(rowIndex, 3).Value = "" Then
                                        Source.Cells(rowIndex, 2).Copy
                                        Destination.Cells(outputrowIndex, 4).Select
                                        Selection.PasteSpecial Paste:=xlPasteValues
                                    End If
                                Next ce

but Column I in the example below is what I am looking to do

Excel 2013 32 bit

	A​	B​	C​	D​	E​	F​	G​	H​	I​
1​	Input	Input	Input				End Result	End Result	End Result
2​	2.1	Title 1				2.1.1	[sub 1]	[sub 2]	Title 1
3​	2.1.1	[sub 1]	[sub 2]			2.1.2	[sub 1]	[sub 2]	Title 1
4​	2.1.2	[sub 1]	[sub 2]			2.1.3	[sub 1]	[sub 2]	Title 1
5​	2.1.3	[sub 1]	[sub 2]			2.1.4	[sub 1]	[sub 2]	Title 1
6​	2.1.4	[sub 1]	[sub 2]			2.1.5	[sub 1]	[sub 2]	Title 1
7​	2.1.5	[sub 1]	[sub 2]			2.1.6	[sub 1]	[sub 2]	Title 1
8​	2.1.6	[sub 1]	[sub 2]			2.1.7	[sub 1]	[sub 2]	Title 1
9​	2.1.7	[sub 1]	[sub 2]			2.1.8	[sub 1]	[sub 2]	Title 1
10​	2.1.8	[sub 1]	[sub 2]			2.1.9	[sub 1]	[sub 2]	Title 1
11​	2.1.9	[sub 1]	[sub 2]			2.1.10	[sub 1]	[sub 2]	Title 1
12​	2.1.10	[sub 1]	[sub 2]			2.2.1	[sub 1]	[sub 2]	Title 2
13​	2.2	Title 2				2.2.2	[sub 1]	[sub 2]	Title 2
14​	2.2.1	[sub 1]	[sub 2]			2.2.3	[sub 1]	[sub 2]	Title 2
15​	2.2.2	[sub 1]	[sub 2]			2.2.4	[sub 1]	[sub 2]	Title 2
16​	2.2.3	[sub 1]	[sub 2]			2.2.5	[sub 1]	[sub 2]	Title 2
17​	2.2.4	[sub 1]	[sub 2]			2.2.6	[sub 1]	[sub 2]	Title 2
18​	2.2.5	[sub 1]	[sub 2]			2.2.7	[sub 1]	[sub 2]	Title 2
19​	2.2.6	[sub 1]	[sub 2]			2.2.8	[sub 1]	[sub 2]	Title 2
20​	2.2.7	[sub 1]	[sub 2]			2.2.9	[sub 1]	[sub 2]	Title 2
21​	2.2.8	[sub 1]	[sub 2]			2.2.10	[sub 1]	[sub 2]	Title 2
22​	2.2.9	[sub 1]	[sub 2]			2.3.1	[sub 1]	[sub 2]	Title 3
23​	2.2.10	[sub 1]	[sub 2]			2.3.2	[sub 1]	[sub 2]	Title 3
24​	2.3	Title 3				2.3.3	[sub 1]	[sub 2]	Title 3
25​	2.3.1	[sub 1]	[sub 2]			2.3.4	[sub 1]	[sub 2]	Title 3
26​	2.3.2	[sub 1]	[sub 2]			2.3.5	[sub 1]	[sub 2]	Title 3
27​	2.3.3	[sub 1]	[sub 2]			2.3.6	[sub 1]	[sub 2]	Title 3
28​	2.3.4	[sub 1]	[sub 2]			2.3.7	[sub 1]	[sub 2]	Title 3
29​	2.3.5	[sub 1]	[sub 2]			2.3.8	[sub 1]	[sub 2]	Title 3
30​	2.3.6	[sub 1]	[sub 2]			2.3.9	[sub 1]	[sub 2]	Title 3
31​	2.3.7	[sub 1]	[sub 2]			2.3.10	[sub 1]	[sub 2]	Title 3
32​	2.3.8	[sub 1]	[sub 2]
33​	2.3.9	[sub 1]	[sub 2]
34​	2.3.10	[sub 1]	[sub 2]

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Sheet: Input

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