You can use a Select Case statement:

Private Sub CommandButton1_Click()
    Select Case True
       Case oB1
          MsgBox "option1"
       Case oB2
          MsgBox "option2"
       Case oB3
          MsgBox "option3"
       Case oB4
          MsgBox "option4"
       Case oB5
          MsgBox "option5"
    End Select
End Sub