The page from Service Employees International Union local 2028 (San Diego) at seiu2028.org/action/issues/mco.cfm has a link entitled "San Diego We Are America/Somos America Alliance", which leads to the (now 404) page cccaction.org/cccaction/waa_index.html, which is similar to the page hosting the We Are America Alliance. And, it includes this:

Our local "We Are America-Somos America" alliance hosted rallies and candleight vigils at San Diego's Balboa Park an Escondido's Grape Day Park in support of immigration reform and workers' rights on May 1st. Our union participating in these rallies in celebration of International Worker's Day, and to build on the momentum we have helped build to end the underground economy that exploits undocumented workers and drives down wages and reduces access to health care and a secure retirement for all Americans.

...Our local "We Are America" alliance is a coalition of faith, labor, civic, community, and student organizations, including the [[Center for Social Advocacy]], [[Justice Overcoming Boundaries]], [[MAAC Project]], [[Border Angels]], [[Gente Unida]], ACORN, [[PIQE]], [[Latinos y Latinas en Accion]], [[Justice for Immigrants Campaign Committee of the Catholic Diocese of San Diego]], Service Employees International Union Locals 1877 and 2028, and the [[South Bay Forum]]...

However, it appears somewhat unlikely that the WAAA and the Somos America group are the same organization.