3 across - harnessed seats for 5 year olds?

[tsl]

We're preparing to carpool with 2 other families and are looking for car seat solutions. The kids are all 5 years old but are used to riding in harnessed seats like the Frontier 85. None of them have any booster experience. It seems like the Safety 1st Go and the Radian seats would be the only options if we want to keep them harnessed, but it seems like a combo would be necessary since my 2010 Prius doesn't have latch in the middle for the Go. Also wondering if the Radian would be overkill since the kids are already 5. I suggested the Safe Rider Travel Vest, but the other families don't think it'll be comfortable.

I'm hoping you all might have some suggestions - thanks!
Tami

[Joolsplus2]

It's funny, parents think kids won't like the RideSafer, but I guarantee you'd have to draw straws every time you get in the car, because all the kids would WANT to be the one to ride in it and you'd have to pick a fair way to share :rotflmao: (My kids loved it, because 'I don't have to sit in a carseat!')
I wonder if the Evenflo Maestro would be narrow enough? It would be inexpensive and makes a great combo seat. Another thing is to install all the seats with seatbelts, instead of LATCH, to give yourself more room to fit a seat in the middle (LATCH is often towards the middle, while with the belt you can install closer to the door). (Do you have a Babies R Us near you? You can try their floor model Maestro in your car to see if it works). The Go installs fine with the seatbelt, once you learn how to do it, it can be a bit challenging to learn, but once it's in, it's in.