At the moment think the best / only way is to have two separate references in your Z database. Then when it comes to citing it you cite them both using the multiple soures and stick "reprinted" in the suffix of the first reference. You then have to use the text editor to get rid of the intervening semi-colon.

I don't think you'll get a better workaround than that at the moment. There is a longer term intention for Zotero to address this (rather tricky) issue by explicitly relating database entries to one another, and then invoking that relationship as needed when citing, but I think the developers are frying other fish (syncing, markup in notes, working collaboratively, improving WP plugins) just now.

Even when the problem is addressed, previous discussion leads me to believe it it will be by formally relating two separate database entries, rather than by including reprint (or original) publication information in the one or the other. So (unless I'm mistaken about this) the above workaround is actually the best way to set up your database now for the forthcoming solution to this issue.

If you have a lot of these you may want to either: (1) mark them as 'related' to one another, using the related tab. This is a basically useless connection at the moment, but it could help you remember which entries you mean to include repub info for (2) give the reprints a common tag, so you can find and fix them all later when this problem is solved, and/or (3) use child notes to remind yourself which items have reprint info. You can't use it automatically in citations, but it could help you remember which items are reprinted (or originals. I tend to cite things by the later/available editon, and note that they were 'originally published as.' The converse of your requirement, but the same problem).

This a good example of a relation/related between 2 items (and not between their communs subjects and contents). The problem is that now we can't name the relation using "related": what does it mean that 2 items are related??? Why are they related? Without the possibility to name it, I don't know how we cant use it really.
So, for now, you can use a Note to name the "related".
a) ad a Note to item 1,and write just "reprint" in it;
b) to this Note ad a "related" (it's possible) to the item 2, wich is the "reprint"

Like that, you'll have name/tag the related "reprint". If you have many cases of reprint for many items you could easily find it searching "reprint" in your notes.
To write it in a bibliography, it's not an easy way...

In the future, in a more hierarchical database, Zotero should create a bibliographic styles with informations from 2 items: the first edition + the infos for the reprint or the second edition.
In an old Access database, I create a system of "related" named "reprint" to create bibliography like that:

Ferron, Jacques, «Suite à Martine» , Amérique française, X: 6, nov.-déc. 1952, p. 29-38; Contes, p. 173-182.

The " ; " is the convention I use in my homemade style to indicate the reprint, but I could have write "reprinted in" or any other expressions at well. And I could have write the references to the reprint "Contes/ Tales", more complete if I like (publishers, year, etc.)...
It's a bibliography written using the infos of 2 items related together. It could be usefull for more cases like translation or new edition, etc.