I'm not so sure about that...
1993: Lilly & Phoebe. Full sisters, also full sisters to Alexander who will be mentioned with regards to other imports.
2013: Billy/Budi. Son of Alexander and Yasmin/SheRa. Nephew of the above mentioned Lilly & Phoebe.
2022: Trong Nhi & Nih Lihn. Trong Nhi's father is Alexander, making Nih Lihn Alexander's granddaughter. Niece and grand(?)-niece of Lilly & Phoebe. Half-sister & half-niece of Billy/Budi.
2023: Yasmin/SheRa, Anak, Kabir & Sanjay. Yasmin/SheRa is the mother of Anak, Billy/Budi & Kabir. Anak is the mother of Sanjay. Both Anak & Billy/Budi were sired by Alexander. Making them full siblings, Lilly & Phoebe's niece & nephew, half-siblings of Trong Nhi & half-aunt/uncle to Nih Lihn.
Kabir & Sanjay were sired by a bull named Upali, who thankfully isn't related to any of the above. However, Kabir is Yasmin/SheRa's son, making him Anak & Billy/Budi's half-brother. And Sanjay's half-uncle via Anak. Sanjay & Kabir are also 3/4 siblings thanks to their maternal relatives and shared father.
So yeah...
When it comes to genetic diversity, those four European imports? Not the best source of it, lol.