OP I’d go with 2 tables and request to be seated in same room. The tables are close enough to each other you still will get that communal feel with your party & hopefully with the others who are seated with you.
We had that experience on our visit a few months ago. 1st table had 5 of the large group seated, plus our party of 3 people. 2nd table had 6, plus a party of 2 (who wound up leaving before dessert was even offered).
Can’t say i blame them. felt quite awkward, as though we were intruding on a private, family meal; so contrary to the general experience you have at a teppan restaurant.