Modify to Run On Specific Column and Remove trailing digits in string

I have a sheet that has an identifier like 1325686468.2958 on each line of column H. The digits leading up to the "." are the one's that matter to me. I need to keep 1 entry for each unique identifier. I have a macro that I picked up that deletes the entire row based on duplicates in the selected column which is great but I need it modified to first eliminate the 4 trailing digits. Also, this identifier will always be in column H, can i make it run there everytime instead of having to select that column first? Any help would be greatly appciated.

Sub RemoveDupes2()
Dim LR As Long
Dim COL As Long

COL = ActiveCell.Column
LR = Cells(Rows.Count, COL).End(xlUp).Row

With Range(Cells(1, Columns.Count), Cells(LR, Columns.Count))
    .FormulaR1C1 = "=IF(COUNTIF(R1C" & COL & ":RC" & COL & ",RC" & COL & ")=COUNTIF(C" & COL & ",RC" & COL & "), 1, """")"
    .SpecialCells(xlCellTypeFormulas, 2).EntireRow.Delete xlShiftUp
    .ClearContents
End With

End Sub