Как в GetOpenFileName выбрать сразу несколько файлов?

Public Declare Function GetOpenFileName Lib _
"comdlg32.dll" Alias "GetOpenFileNameA" _
(pOpenfilename As OPENFILENAME) As Long
 
Public Const OFN_HIDEREADONLY = &H4
 
Public Type OPENFILENAME
lStructSize As Long
hwndOwner As Long
hInstance As Long
lpstrFilter As String
lpstrCustomFilter As String
nMaxCustFilter As Long
nFilterIndex As Long
lpstrFile As String
nMaxFile As Long
lpstrFileTitle As String
nMaxFileTitle As Long
lpstrInitialDir As String
lpstrTitle As String
flags As Long
nFileOffset As Integer
nFileExtension As Integer
lpstrDefExt As String
lCustData As Long
lpfnHook As Long
lpTemplateName As String
End Type
 
Public Function ShowOpen() As String
Dim strTemp As String
Dim VertName As OPENFILENAME
VertName.lStructSize = Len(VertName)
VertName.hwndOwner = ThisDrawing.HWND
VertName.lpstrFilter = "AutoCAD Files (*.dwg)" + _
Chr$(0) + "*.dwg" + Chr$(0)
VertName.lpstrFile = Space$(254)
VertName.nMaxFile = 255
VertName.lpstrFileTitle = Space$(254)
VertName.nMaxFileTitle = 255
VertName.lpstrInitialDir = CurDir
VertName.lpstrTitle = "Открытие файлов"
VertName.flags = 0
 
If GetOpenFileName(VertName) Then
strTemp = (Trim(VertName.lpstrFile))
ShowOpen = Mid(strTemp, 1, Len(strTemp) - 1)
End If
End Function