Using VBA - Insert VLOOKUP depending on certain values - vba

Question

I am trying to retrieve data from another file using the VLOOKUP function however this is only to happen depending on if any of the 3 items of data appear in column 8(H)
OLY
OLY - QUO
OLY - PRO
I have the following and know this is not correct
Sub BlockAllocationsVlookupAll()
Dim x As Long
For x = 1 To 65536
If InStr(1, Sheet1.Range("$H$" & x), "OLY") > 0 Then
Sheet1.Range("$I$" & x) = Sheet1.Range("$I$" & x) & "sometext"
End If
Next
End Sub
I know the above doesn't do exactly what I need can anyone help as to what needs to be edited to include the Vlookup below
=VLOOKUP(A21,'[001 - Allocations - Blocks.xls]CurrentDayAll'!$1:$65536,9,FALSE)
The other issue is that the cell the VLOOKUP points to first will also change due to the varying length of the report
Thank you for any help given

Answer 1

UPD:
As follows up from comments,
column H is in Allocations.xls workbook
there are a set of criterias
formula should be placed in cell only if corresponding cell in column H matches any of thouse criterias.
Working code:
Sub BlockAllocationsVlookupAll()
Dim x As Long
Dim lastrow As Long
Dim searchCriterias As String
Dim wb As Workbook
Dim ws As Worksheet
'specify correct path to your workbook
Set wb = Workbooks.Open("C:\Allocations.xls")
'If workbook is already opened use next line
'Set wb = Workbooks("Allocations.xls")
Set ws = wb.Worksheets("Current Day")
searchCriterias = "|OLY|SVC|SVC-PRO|SVC-QUO|EUR|EUR-PRO|EUR-QUO|"
With ws
lastrow = .Cells(.Rows.Count, "H").End(xlUp).Row
For x = 4 To lastrow
If InStr(1, searchCriterias, "|" & .Range("H" & x) & "|") > 0 Then
.Range("I" & x).Formula = "=VLOOKUP(A" & x & ",'[001 - Allocations - Blocks.xls]CurrentDayAll'!$A:$I,9,FALSE)"
End If
Next
End With
'Comment next line if you don't want to close wb
wb.Close (True)
Set wb = Nothing
End Sub