You could use a macro like:
Code:
Sub Demo()
Application.ScreenUpdating = False
Dim StrFnd As String, StrSty As String, i As Long
StrFnd = "1,2,3,4,5"
StrSty = " Strong,Heading 1,Character Style 1,Italic,Character Style 2"
With ActiveDocument.Range.Find
.ClearFormatting
.Replacement.ClearFormatting
.Forward = True
.Format = True
.Wrap = wdFindContinue
.MatchWildcards = True
For i = 0 To UBound(Split(StrFnd, ","))
.Text = "#" & Split(StrFnd, ",")(i) & "[A-Za-z]@>"
.Replacement.Style = Split(StrSty, ",")(i)
.Execute Replace:=wdReplaceAll
Next
End With
Application.ScreenUpdating = True
End Sub