Hide particular Req

I want some particular Req to be hide from particular the users. I have added the following code into the workflow..but its not working

if Req_Fields.Field("RQ_REQ_ID").Value = "Req ID" AND User.IsInGroup("DemoGroup")  then

For j= 0 To Req_Fields.Count -1
 Req_SetFieldApp Req_Fields.FieldByID(j).FieldName, False, False, 0, 1
Next

Sub Req_SetFieldApp( FieldName, ReadOnly, Vis, Req, PNo, VOrder )
On Error Resume Next
With Req_Fields(FieldName)
.IsReadOnly = ReadOnly
.IsVisible = Vis
.IsRequired = Req
.PageNo = PNo
.ViewOrder = VOrder
End With

On Error GoTo 0
End Sub