One top-flight fixture per season is due to be staged on US soil starting next term as part of a 15-year agreement designed to promote the competition's global appeal.
The proposal has been met with firm opposition from the players, who claim to have been excluded from the decision-making process and are not ruling out strike action.
Busquets, the AFE's vice president, declared La Liga's playing base to be in unison on the issue.
"We're all united, the union is strong and as our president [David Aganzo] has said, we all think the same about this," the 30-year-old said in a video released by the association.
"Together we are stronger and this is a path that we all want to take and we believe it's what is best for football."
After a meeting on Wednesday, Aganzo described the players as "outraged" and "very surprised" by the decision.
Organisers are yet to state which fixtures are being considered for the annual affair, although La Liga president Javier Tebas has deemed it "unfeasible" for the Clasico between Barcelona and Real Madrid to be played in New York.