Yes. Submitted project proposals may include principal investigators (PIs) and co-investigators (Co-Is) who are not affiliated with any of the three ALMA Executive regions. Please refer to sections 3.3 and 3.4 of ALMA Cycle 0 Proposer's Guide (ver 1.1 May 2011). See also the related KB article:
https://help.almascience.org/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=93
https://help.almascience.org/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=93