You need to conditionally process the stores e.g.
Private Sub Application_Startup()
Dim objStores As Outlook.Stores
Dim objStore As Outlook.Store
Dim objPSTFile As Outlook.Folder
Dim objFolders As Outlook.Folders
Dim objFolder As Object
Set objStores = Outlook.Application.Session.Stores
'Process all Outlook PST files in your Outlook
For Each objStore In objStores
Select Case objStore.DisplayName
Case Is = "Name of Store1", "Name of Store2"
Set objPSTFile = objStore.GetRootFolder
For Each objFolder In objPSTFile.Folders
Call ProcessFolders(objFolder)
Next objFolder
Case Else
End Select
Next objStore
Set objStores = Nothing
Set objStore = Nothing
Set objPSTFile = Nothing
Set objFolders = Nothing
Set objFolder = Nothing
End Sub
Where "Name of Store1", "Name of Store2" are the display names of the accounts you wish to process. If you are unsure what names to use, the following will list the store display names in the immediate window
Sub Test()
Dim objStores As Outlook.Stores
Dim objStore As Outlook.Store
Set objStores = Outlook.Application.Session.Stores
'Process all Outlook PST files in your Outlook
For Each objStore In objStores
Debug.Print objStore.DisplayName
Next objStore
Set objStores = Nothing
Set objStore = Nothing
End Sub