The following code will do what you want.
I have used an Access table containing two fields, one for your data, and the second for the replaced data (group of spces replaced with a Tab) data to achieve the result.
The table details I have used are :
TableName = YourTable
Fields YourFieldName (Text, 255)
ReplacedField (Text, 255)
You can change the above to what you want and make the appropriate changes in the code I have forwarded to you.
IMPORT your text file data into the field "YourFieldName" and then run the following. The results you want will end up in the field "ReplacedField"
Public Function Replace_Spaces_With_Tabs()
On Error GoTo Error_in_Replacement
Dim db As Database
Dim rst As Recordset
Dim FieldLength As Long
Dim StartPoint As Long
Dim CharacterToReplace As Long
Dim NewField As String
Dim SingleCharacter As String * 1
Set db = CurrentDb
Set rst = db.OpenRecordset("YourTable"
rst.MoveFirst
Do Until rst.EOF = True
FieldLength = Len(rst!Yourfieldname)
NewField = " "
StartPoint = 1
' Replace each group of spaces with a single Tab character
Do Until StartPoint > FieldLength
CharacterToReplace = InStr(StartPoint, rst!Yourfieldname, " "

If CharacterToReplace = 0 Then
' Nothing more to replace - so build last input group and exit
NewField = NewField & Mid(rst!Yourfieldname, StartPoint, (FieldLength - StartPoint) + 1)
StartPoint = FieldLength + 1
Else
' Build current group of characater ready for output with a TAB replacing the group of spaces
NewField = NewField & Mid(rst!Yourfieldname, StartPoint, (CharacterToReplace - StartPoint))
NewField = NewField & vbTab
' Now look for the next input character that is NOT a space
SingleCharacter = " "
StartPoint = CharacterToReplace
Do Until SingleCharacter <> " " Or StartPoint > FieldLength
StartPoint = StartPoint + 1
SingleCharacter = Mid(rst!Yourfieldname, StartPoint, 1)
Loop
End If
Loop
' Update second field within current record with the replaced details
rst.Edit
rst!ReplacedField = LTrim(NewField)
rst.Update
' Get next input record
rst.MoveNext
Loop
rst.Close
db.Close
Exit_This_Function:
Exit Function
Error_in_Replacement:
MsgBox "Error detected"
Resume Exit_This_Function
End Function