A Riemannian manifold
$\left( M,\,\rho \right)$ is called Einstein if the metric
$\rho $ satisfies the condition
$\text{Ric}\left( \rho \right)\,=\,c\,\cdot \,\rho $ for some constant
$c$. This paper is devoted to the investigation of
$G$-invariant Einstein metrics, with additional symmetries, on some homogeneous spaces
$G/H$ of classical groups. As a consequence, we obtain new invariant Einstein metrics on some Stiefel manifolds
$SO\left( n \right)/SO\left( l \right)$. Furthermore, we show that for any positive integer
$p$ there exists a Stiefel manifold
$SO\left( n \right)/SO\left( l \right)$ that admits at least
$p$
$SO\left( n \right)$-invariant Einstein metrics.