The previous example may be re-worked using a With (Recursive) Group, while yielding the same results.
Example - With (Recursive) Group

The SQL generated by the base query in this case is:
WITH RECURSIVE "Referral Seed 1" ("cust_id", "level") AS (SELECT "_twmSQ0"."cust_id" AS "cust_id" ,0 AS "level" FROM "twm_results"."_twm_referral" AS "_twmSQ0" WHERE "_twmSQ0"."referred_by" = 1362480 UNION ALL SELECT "_twmVC0"."cust_id" AS "cust_id" ,"_twmVC1"."level" + 1 AS "level" FROM "twm_results"."_twm_referral" AS "_twmVC0" , "Referral Seed 1" AS "_twmVC1" WHERE ("_twmVC1"."cust_id" = "_twmVC0"."referred_by") AND ("_twmVC1"."level" <= 3) ) , RECURSIVE "Referral Seed 2" ("cust_id", "level") AS (SELECT "_twmSQ0"."cust_id" AS "cust_id" ,0 AS "level" FROM "twm_results"."_twm_referral" AS "_twmSQ0" WHERE "_twmSQ0"."referred_by" = 1362489 UNION ALL SELECT "_twmVC0"."cust_id" AS "cust_id" ,"_twmVC1"."level" + 1 AS "level" FROM "twm_results"."_twm_referral" AS "_twmVC0" , "Referral Seed 2" AS "_twmVC1" WHERE ("_twmVC1"."cust_id" = "_twmVC0"."referred_by") AND ("_twmVC1"."level" <= 3) ) SELECT DISTINCT * FROM "Referral Seed 1" UNION ALL SELECT DISTINCT * FROM "Referral Seed 2" ;
In this example, the result set is exactly the same as in the previous example.