If you could run the flue under the floor of the bread oven it might give you what you want but doubt it'll conform to building regs and I'd be dubious of the draw you'd get.
That said, my wood burning range cooker (in the process of making) has a simple flue damper that lets all the hot gas straight up the chimney. Once a good draw is established, the damper can be closed and the hot gases have no option but to circulate around the ovens - essentially what you're proposing.
It's a lot of pipework, though, but doable, I'd say