The short answer is 'no' - at least not in a single pass; but it is easy enough to do with a macro
Sub Highlight()
Dim vFindText As Variant
Dim oRng As Range
Dim i As Long
vFindText = Array("custom", "treaty")
For i = 0 To UBound(vFindText)
Set oRng = ActiveDocument.Range
With oRng.Find
.ClearFormatting
.Replacement.ClearFormatting
Do While .Execute(FindText:=vFindText(i), _
MatchWholeWord:=True, _
Forward:=True, _
Wrap:=wdFindStop) = True
oRng.HighlightColorIndex = wdYellow
oRng.Collapse wdCollapseEnd
Loop
End With
Next
lbl_Exit:
Exit Sub
End Sub