The largest umbrella group for the men is the Great War Veterans' Association. It was established in 1917 after a number of failed or modest attempts by the government to assist soldiers upon their return:
"... the returning soldiers began to create their own organizations. The most powerful of these was the Great War Veterans' Association. Through these organizations, the soldiers pressured the government to give preference to veterans when hiring and to increase pensions for common soldiers, widows, and the disabled". source
Officially, the GWVA was neutral but that changed today. At a boisterous meeting at the GWVA hall the following resolution was put forth from the floor over the attempts of the chair to overrule it.
The motion passed with the required majority. The GWVA is now on-side with the strike.
The next day it was announced that the GWVA executive voted to cancel all meetings of the organization until fourteen days after the strike was declared over.
Also see "From Great War Veterans' Association to the Legion"