What age are your grandchildren and what types of carseats are they in? As posted above, seatbelts work just as well as Latch - the only advantage of Latch is how quickly you can install/remove the seat. If your grandkids are in rear facing seats, the seatbelts should be fine. If they're in boosters there's no problem. However, if they're in forward facing harness seats they will require anchors for the tethers. You can pick those up from your local auto parts store and have your mechanic or bodyshop drill and reinforce them into the floorboard. In case you're wondering how safe that is, I did the same thing with my '95 Jeep YJ. Those anchors have held firm for five years now.