We have an Odyssey. We have 3 kids but they are not all still in carseats now. We do not need to install 3 seats at once, but I have moved them around to different positions depending on how many adults were traveling with us. You would have to put two in the middle row and one in the third row. I would choose the middle spot in back.
Oh, I just reread and see you said more than three. You can for sure fit four carseats, two in the middle and two in the back. There are seatbelts for three in the back row so you could technicly fit 3 in that row but it might be quite crowded. It might depend on the type of seats.