Compare Two Cells & Return Whats Common Between the two strings and delete the variation

Here's my version

In cell E2

=IF(C1<>C2,GetMaxCommon(B2,$B$2:$C$51,C2,FALSE),"")

Then fill down to the bottom of the table

Function GetMaxCommon(ByVal txt As String, rng As Range _
    , myGroup As Long, CSense As Boolean) As String
    Dim r As Range, x, i As Long, temp As String, m As Object, Pos As Long, n As Long
    Static RegX As Object
    If RegX Is Nothing Then
        Set RegX = CreateObject("VBScript.RegExp")
        RegX.IgnoreCase = Not CSense
    End If
    x = Split(txt)
    Pos = UBound(x)
    For Each r In rng.Columns(1).Cells
        If (r.Value <> txt) * (r(, 2).Value = myGroup) Then
            temp = r.Value
            With RegX
                For i = 0 To UBound(x)
                    .Pattern = x(i)
                    If .test(temp) Then
                        Set m = .Execute(temp)(0)
                        If m.FirstIndex <> 0 Then
                            n = i - 1
                            Exit For
                        Else
                            temp = Trim(Mid$(temp, m.Length + 1))
                        End If
                    Else
                        n = i - 1
                        Exit For
                    End If
                Next
                If Pos > n Then Pos = n
            End With
        End If
    Next
    ReDim Preserve x(Pos)
    GetMaxCommon = Join$(x)
End Function

Remove Variation With Function.xlsm