howto package kernel-like

[Mihamina Rakotomandimby]

Hi,
I would like to make a package behaving like the kernel:
When a new version is available, it installs near the old version, but
it does not replace the old version.
Has that kind of package a special name? What keyword or special
mentions have I got to place in the spec file to get this behaviour?
Of course, the install name/directory will be different as of the
versions.
Thank you.