ここに使用できる機能があります。コメントとコードは一目瞭然です
コード:
Function SplitThis(InputStr As String) As Variant
Dim SplitStr() As String, SubStr() As String, RightmostStr As String
Dim OutputStr() As String
Dim Delim_Level1 As String, Delim_Level2 As String, Delim_Cut As String
Delim_Level1 = "\"
Delim_Level2 = " "
Delim_Cut = "}" ' Any character you are guaranteed not to find in your original string
'InputStr = "Domain\Domain Admins Domain2\User Group Domain3\Developer"
SplitStr = Split(InputStr, Delim_Level1)
' SplitStr(0) = "Domain"
' SplitStr(1) = "Domain Admins Domain2"
' SplitStr(2) = "User Group Domain3"
' SplitStr(3) = "Developer"
Dim i As Long
For i = 1 To UBound(SplitStr) - 1 ' i.e. 1 --> 2
SubStr = Split(SplitStr(i), Delim_Level2)
RightmostStr = SubStr(UBound(SubStr))
ReDim Preserve SubStr(0 To UBound(SubStr) - 1)
SplitStr(i) = Join(SubStr, Delim_Level2) & Delim_Cut & RightmostStr
Next i
' SplitStr(0) = "Domain"
' SplitStr(1) = "Domain Admins{Domain2"
' SplitStr(2) = "User Group{Domain3"
' SplitStr(3) = "Developer"
' These are joined to create:
' "Domain\Domain Admins}Domain2\User Group}Domain3\Developer"
'
' Which is split at the character "}" to create the output
OutputStr = Split(Join(SplitStr, Delim_Level1), Delim_Cut)
Dim OutputVariant() As Variant
ReDim OutputVariant(0 To 0, 0 To UBound(OutputStr))
For i = 0 To UBound(OutputStr)
OutputVariant(0, i) = OutputStr(i)
Next i
SplitThis = OutputVariant
End Function
使用法:
Cell A1 : "Domain\Domain Admins Domain2\User Group Domain3\Developer"
Cell A3:C3: {=SplitThis(A1)} ' Array formula
スクリーンショット:

しつこい疑問:Regex
これを行う最も効率的な方法は、何らかのベースのソリューションを使用することだと感じていますが、今のところはこれで十分です。