On finite totally $2$-closed groups

An abstract group $G$ is called totally $2$-closed if $H=H^{(2),\Omega }$ for any set $\Omega $ with $G\cong H\le \mathrm{Sym}(\Omega )$, where $H^{(2),\Omega }$ is the largest subgroup of $\mathrm{Sym}(\Omega )$ whose orbits on $\Omega \times \Omega $ are the same orbits of $H$. In this paper, we classify the finite soluble totally $2$-closed groups. We also prove that the Fitting subgroup of a totally $2$-closed group is a totally $2$-closed group. Finally, we prove that a finite insoluble totally $2$-closed group $G$ of minimal order with non-trivial Fitting subgroup has shape $Z\cdot X$, with $Z=Z(G)$ cyclic, and $X$ is a finite group with a unique minimal normal subgroup, which is nonabelian.