The boys are as far from the Jewish "bubble" as they can be. And their mothers similarly grew up outside the main centres of Anglo-Jewish life, Hannah Grainger in Norwich, Gaby Swain in "deepest Somerset", a pupil of Wells Cathedral School.
The boys share something else too. Every month they receive a package containing children's books on Jewish themes; attractive, colourful books, fiction and non-fiction, about Judaism, festivals, Shabbat, Israel, Jewish people and families.
These books help Zachary, Sam and Sam's brothers expand and strengthen their Jewish identities. Their mothers say they are a "lifeline".
The books come from PJ Library, an organisation set up by an elderly man from Massachusetts. Harold Grinspoon made a fortune in property, then established a charitable foundation to build Jewish identity and invigorate Jewish life globally while ensuring a strong state of Israel.
One of the foundation's main initiatives was PJ Library, which started by sending books to 200 families in Massachusetts, expanded rapidly and has distributed more than seven million books in North America in the past 10 years.
In 2011 the service went global and now provides books to families in countries including Australia, Mexico, Singapore, Costa Rica, El Salvador, Guatemala, Uruguay and Russia. The programme started in the UK in 2015 and there is so much demand that there is currently a waiting list.
Mr Grinspoon wanted to give children something his childhood lacked. "I had no exposure to Jewish stories when I was a child," he says.
"This is part of the inspiration for PJ Library. It's our collective responsibility to make sure Jewish children and families are raised with Jewish stories and conversations."
"My boys really look forward to the books arriving every month," says Mrs Grainger, who has put her career as a teacher on hold for a few years to be a full-time mum to Sam, Gabriel, aged four, and Isaac who is nearly two.
She heard about PJ Library from a friend at the Orthodox synagogue in Norwich. The shul's cheder, comprising eight children aged from three to eight love discussing their PJ books. "It's a focus for all of them," she says.
The Grainger family also goes to the town's Liberal synagogue and they share the books there too.
Hannah's husband James is not Jewish but is happy to support her efforts to bring the boys up as Jews. "The books are a very accessible way for him to learn more about my culture and faith, and feel involved in passing that on to the boys," she says.
"The books support their Jewish identity. Sam is aware that he's different, that he's not like the other children. Reading the books helps him to feel good about that.
"We enjoy reading them as a family. They help keep that side of life going. And often they'll give me a nudge to do something extra. For example, it'll be Tu b'Shvat and we'll read something about it and then think what can we do at home or at cheder to mark the day."
The PJ Library book on Tu b'Shvat was also an inspiration for Gaby Swain, who set up a toddler group, the Dreidl Dribblers, attached to Exeter Synagogue. They celebrated the festival by reading their PJ Library book and then planting tomato and sunflower seeds.
"Our community is very small, and has no rabbi," she says. "PJ Library gives us access to Jewish resources, and it's free - it's a lifeline for us. In small communities you can't wait for other people to start something for you - you have to do it for yourself."
In Exeter there are four or five families who come together for Jewish activities and education, including a camping trip in the summer. Mrs Swain says: "We used our PJ Library books to talk about havdalah, and then lit our candle - we got some funny looks from random ramblers."
Mrs Swain, who teaches at a school for the blind and visually impaired in Exeter, and her friend Emma Sadeghi are hoping to work with PJ Library to plan lessons for the shul's cheder.
She says: "The whole PJ Library resource is invaluable. Down here, most people have never met a Jewish person. But I know from growing up in Somerset that it's possible to live in rural areas and still have a strong Jewish identity."
Mr Grinspoon visited England this week to encourage donations to match his investment in expanding PJ Library to be able to send books to the hundreds on its waiting list in the UK.
"Every Jewish child should have the opportunity to receive the books, songs and Jewish activities from PJ that spark Jewish moments and conversations."
Sam and Zachary would no doubt agree.
