Public Sub splitUpRegexPattern()
Dim regEx As New RegExp
Dim strPattern As String
Dim strInput As String
Dim strReplace As String
Dim Myrange As Range

Set Myrange = ActiveSheet.Range("B2:B4279")

For Each c In Myrange
    strPattern = "([A-Z]{2}/[A-Z]{2}/[A-Z][0-9]{2}/[a-z]{3}[0-9]{9}/)([0-9]{4})"

    If strPattern <> "" Then
        strInput = c.Value
        strReplace = "$1"

        With regEx
            .Global = True
            .MultiLine = True
            .IgnoreCase = False
            .Pattern = strPattern
        End With

        If regEx.test(strInput) Then
            c.Offset(0, 1) = regEx.Replace(strInput, "$2")
        Else
            c.Offset(0, 1) = ""
        End If
    End If
Next