Short answer. Three. Article 38 provides that illegal recruitment is deemed committed by a syndicate if carried out by a group of three or more persons conspiring or confederating with one another. Two people working together is not a syndicate, however organised the operation looks from the outside.
What the law says
Illegal recruitment is deemed committed by a syndicate if carried out by a group of three (3) or more persons conspiring and/or confederating with one another in carrying out any unlawful or illegal transaction, enterprise or scheme
Labor Code, Article 38 — Illegal Recruitment Defined. Read the full provision →
The number is people, not roles
Three or more persons, counted as individuals. A single agency with three officers involved can satisfy it; so can three unconnected people who agreed to work a scheme together. What the clause does not count is functions — an operation run by two people wearing several hats each is still two people. It also does not count the applicants; the victims are counted under the separate large-scale test. Getting this straight matters, because a complaint that describes a "syndicate" while naming two individuals invites the wrong answer.
Conspiring or confederating has to be shown
Three names alone are not enough. The provision requires that they were conspiring and/or confederating with one another in carrying out any unlawful or illegal transaction, enterprise or scheme, so what has to appear is a common design rather than three people who happened to be in the same office. The evidence is usually mundane and already in your possession: who introduced whom, who received the money and who issued the receipt, who conducted the interview, whose account or number the transfer went to, and the messages in which they refer to each other.
Why the classification is worth establishing
Illegal recruitment committed by a syndicate is treated as an offence involving economic sabotage under the same article, which puts it in the gravest category the recruitment provisions carry. It also changes who is answerable. Where a common design is shown, the person who merely collected payments cannot easily present himself as an unwitting helper who never promised anyone a job. That is the defence syndicated cases most often meet, and the reason the small details of who did what are worth writing down early.
Record the cast, not just the harm
Most people describing what happened to them lead with the loss and mention the individuals in passing. Reverse that. List every person you dealt with, what each one did, when, and how you know they were connected — a shared office, a referral, one answering for another, a receipt in one name for money handed to a second. Keep screenshots showing names and numbers, not only amounts. Other applicants will have dealt with a different mix of the same people, which is often how the group becomes visible.