People of Rig Vedas do fits in and they were before the period of Prophet Ibrahim.
Ancient Jews were a spiritual union who were consist of people of many tribes who use to worship the God of Abrahim.
And when Exodus took place from Egypt to Palestine under Prophet Moses . 12 banners were raised and these 12 banners were on the 12 Children of Jacob aka Yakub in which people of even other tribes who were not from the Children of Yakub migrated towards Palestine.
Rabbi Joshua interpreted it thus: fivefold they came out of Egypt,
for five times their number in converts were gathered into the people of Israel upon their departure from Egypt.(Midrash Tanchuma)
Parshah In-Depth - Beshalach