Another child new car ^^ please for suggestions help

Hello together, currently I drive a Opel Astra Kombi H. So far it has fit. with 2 children 1 week centerparc fully loaded Angelequipment / stroller suitcase works. Actually the family planning was finished……..but now there is a third and now it gets tight in the station wagon. I still have time (6 months) but you have to look around. I would like to stay with Opel because I have a good dealer nearby and I have no problems with my Opels so far I have selected the market for myself. Important 3 child seats have to fit and more than 5 seats. The children are 8 years 2 years old and last in June 2017 the third one. Zafira: Is actually a family car but the middle seat is locked for children’s seats? Is there the zafira with 7 seats? Opel Combo: Did I actually find ideal neat storage space but there are only rarely vehicles with 7 seats? Bzw. are the 7 seats no longer built? Opel Vivaro: Maybe too big, has Definitely enough space even if you have to take the parents-in-law with you who are now already 74. Do you have experience values? Which cars you drive with 3 children Thanks for help and tips.