return a list of matrices by applying if-else function by a sequence of conditions on a list of matrices

Question

I have a list of matrices:

set.seed(100)
X1 <- mvrnorm(n=4, mu = rep(0, 5), Sigma = (matrix(1,5,5)+diag(5)))
X2 <- mvrnorm(n=4, mu = rep(0, 5), Sigma = (mat