Yes I think in Hindus, it is not allowed and cousins are treated like siblings.
@ Lakshmi. that is a new fact I came to know that bua's children could have intermarried, is that true ? Otherwise I have seen in dramas that all sorts of cousins are considered siblings. (eg in Bidaai n SGP)
[ I am always clearing up confusions abt other cultures... 😊]
Yes. In almost all Hindu cultures; it is possible to marry bua's children😊. But now a days no one prefers marriages from close relations because it is genetically dangerous.