Sub Foo()
    Dim regex As Object
    Set regex = CreateObject("VBScript.RegExp")
    regex.Global = True
    regex.Pattern = "(\((?>[^()]+|(?1))*\))"

    ' aa(bb)cc
    ' (aabbcc)
    ' (aa)bb(cc)
    Debug.Print regex.Test("aa(bb)cc")
End Sub