Packaging OCaml repositories that define multiple packages?

[Csepp]

I'm going through my MirageOS commits for what is hopefully the last
time before I send the patches and I realized that a problem that I
thought was isolated is a lot more widespread than I thought.

As an example look at https://github.com/mirage/mirage/

It defines functoria, functoria-runtime, mirage, and mirage-runtime.

It is possible to build all 4 as one package.

The opam importer seems to not be able to handle situations like this,
since it defines a new package for each sub-package.

How should I proceed?  I definitely want to merge all redundant packages
into one, but then what?  How should the package description reflect
this?  What should the package be named when it corresponds to 4 OPAM
packages at once?

For now I defined a few aliases for cases like this, but I'm not sure if
this is ideal.  They look like this (made up but possible example):
(define ocaml-mirage ocaml-mirage-runtime)