You wouldn't multiply the volts, you'd multiply the amps, by using a separate sub-breaker for each shop, which you're doing anyway since you want to meter them separately.

This is already the norm in lots of Europe. It's not some weird new thing. In Sweden, no mall food courts have natural gas hookups, it's all three-phase electrical appliances. It's been like this forever (since Sweden has craploads of hydro and nuclear and zero gas).