"We need one process for all release management!" is the guiding principle of so many organizations that are trying to implement a modern release-management infrastructure. The reality is that there need to be many processes.
There might be one main high-level release management process that defines the major milestones that we measure our progress against. We could call that a macro milestone process.
Still, there have to be many minor release processes that accommodate the various factors that guide each development team -- such as its technology, time-to-market pressures, risk aversion, development methodology and project complexity. These can be called micro milestone processes.
Let us not forget we need an emergency release process for those patches that have to be fast-tracked through the system.