By the time of the Battle of Kurukshetra, Sini's grandson Satyaki, now a king of the Vrishnis, was allied with the Pandava army while Bhurishravas, now aged, sided with the Kauravas and was one of the eleven commanders of the Kaurava army.
The Kauravas with the Panchalas, the Salwas, the Matsyas, the Naimishas, the Koshalas, the Kasapaundras, the Kalingas, the Magadhas, and the Chedis who are all highly blessed, know what the eternal religion is. (8,45)
Shiva, pleased with his bravery, gives him the powerful weapon, the Pashupatastra, which later in the Mahabharata aids him against Karna and the Kauravas during the Kurukshetra war.
Similar to the other South Indian Kshatriya clans the Kondas too may have claimed descent ultimately from the Mahabharata Kauravas.
During the time of Kurukshetra War, and the reign of Pandavas and Kauravas, we find mention of numerous kingdoms with the name, Kosala (as per the references in Mahabharata).
On a particular day in the Kurukshetra battle due to absence of Arjuna fighting elsewhere, Jayadratha could stop the Pandavas (except Arjuna) and helped kill Abhimanyu treacherously for Kauravas.