My probability on this point is that the influence of travel companions is not a determinant factor, but rather a condition that modulates destination selection, with a confidence band of 60 to 80%. We tend to overestimate the power of a group when individual preferences are strong and alternatives exist.
I often see in the Netherlands groups of friends where, if consensus isn't reached, some leave alone or form subgroups for different activities, like fietsen outside the city.
Hierarchy isn't stable; it heavily depends on group dynamics and alternative solutions considered.