I have this in my config which works very well. I use this just for org :)
I build org from its master branch, so I do not want the dependency check
to auto-install older versions from Elpa.

;; http://emacs.stackexchange.com/a/26513/115
(defun modi/package-dependency-check-ignore (orig-ret)
  "Remove the `black listed packages' from ORIG-RET.
Packages listed in the let-bound `pkg-black-list' will not be auto-installed
even if they are found as dependencies.
It is known that this advice is not effective when installed packages
asynchronously using `paradox'. Below is effective on synchronous
package installations."
  (let ((pkg-black-list '(org))
        new-ret
        pkg-name)
    (dolist (pkg-struct orig-ret)
      (setq pkg-name (package-desc-name pkg-struct))
      (if (member pkg-name pkg-black-list)
          (message (concat "Package `%s' will not be installed. "
                           "See `modi/package-dependency-check-ignore'.")
                   pkg-name)
        ;; (message "Package to be installed: %s" pkg-name)
        (push pkg-struct new-ret)))
    new-ret))
(advice-add 'package-compute-transaction :filter-return
#'modi/package-dependency-check-ignore)

https://github.com/kaushalmodi/.emacs.d/blob/master/setup-packages.el

On Thu, Mar 2, 2017 at 7:41 PM Tim Cross <theophilusx@gmail.com> wrote:

> Is there a way to specify alternative dependencies in a package?
>
> Situation: installing a package is resulting in an additional package
> being installed even though the dependencies for the package have already
> been satisfied by another package. This results in two packages being
> installed which provide overlapping functionality.
>
> Example. I have installed org-plus-contrib. I then install elfeed-org,
> which has a dependency on org. This results in the org package being
> installed, but org is already installed as part of the org-plus-contrib
> package.
>
> I'm trying to work out if this is a problem with how dependencies are
> defined in the elfeed-org package or is it a problem with how
> org-plus-conrib is specifying what dependency it satisfies? Need to know in
> order to determine where this issue needs to be logged.
>
-- 

Kaushal Modi