[antlr-interest] How to resolve this warning?

[Dong, Eric]

Hi Experts:
         Now I confront a warning, and I don't know how to fix it. Detail info below:

Warning:
Warning: alts 1 and 2 of {..} ambiguous upon ( "\|" OpenBrace )

Related code is the following:
  {
    ClassGuid "=" guidDefinition[ClassGuid1]        << ++ClassGuidNum; >>
                  {
                   "\|" guidDefinition[ClassGuid2]  << ++ClassGuidNum; >>
                  }
                  {
                   "\|" guidDefinition[ClassGuid3]  << ++ClassGuidNum; >>
                  }
                  ","
  }

Thanks,
Eric