I guess the mechanism is supposed to be the same, in that GB members are supposed to be members of congregations, and if a matter arises (such as a GB member getting caught in flagrante) then it would be brought to the other elders.
I’ve heard Brooklyn Heights congregation mentioned a few times. A recent YouTube video features an interview from someone who processed field service reports for Splane and Jackson as members of Brooklyn Heights congregation. And an older JW mentions that there were 4 members of the GB in Brooklyn Heights congregation in the 1970s.
But it seems GB members are not full participants in congregations. They are frequently absent attending other business, and I doubt they do the regular work of local elders in any meaningful way. In fact I wonder if they will continue as members of congregations in Warwick because it won’t be as easy to attach to local congregations away out in the middle of nowhere. They may form congregation-like groups comprising solely members of the headquarters instead. This would further distance GB members from the everyday lives of other JWs.