Wikipedia articles are stored in wikidata according to concept
Often, two concepts that are similar to each other but different would be stored separately in wikidata
In these cases, the current solution is to use either the Template:Interwiki_extra on local wikipedia or old-style interwiki link which are both cumbersome and does not fit with the model of storing all the info in wikidata.
These solutions aren't being maintained and monitored across all the different wikis either
Often, that would mean users cannot jump from a wiki language version A with a concept 1 to a wiki language version B with a concept 1*, unless the user really know well about wikidata system and click into wikidata and check related wikidata item
Who would benefit:
All users in all wikimedia projects trying to check out interlanguage links.
Use a wikidata property on all the items that this method can be applied with value being other wikidata items.
For all wikidata item using the property, after checking the interlanguage link within same wikidata item, the program should also look for if there are any missing language version in any of those other linked wikidata items. If there are such wiki version, then they should also be served as a interwiki link to end users.
Proposer: C933103 (talk) 20:40, 11 November 2017 (UTC)
So this is not so much really a wikidata request (adding a property like this ought to be straightforward) - what you are proposing is a modification of the UI on all the mediawiki platforms to pull interwiki links from other items. I think it's a reasonable approach to solving this problem, something along these lines is needed. ArthurPSmith (talk) 20:13, 15 November 2017 (UTC)
I don't think "pulling entries from different wikidata items" is a UI problem.C933103 (talk) 21:18, 15 November 2017 (UTC)
d:Q3008463 is about human-powered cars on railroad. Article for the concept have been created in English, French, Dutch, and Chinese Wikipedia.
d:Q42832982 is about railroad system that use human-powered cars. Article for the concept have been created in German, Italian, Japanese, and Korean Wikipedia.
And then d:Q381727 is about such system in Taiwam, which is available in English and Chinese Wikipedia.
Of course the topic between these three subjects would overlap, however there are currently no mechanism in wiki that could allow visitor to jump between the English wiki version article for handcar and Japanese wikiversion article for handcar railway despite the handcar article would also discuss about railway using them and handcar railway article would also discuss the railway they are used.C933103 (talk) 20:18, 21 November 2017 (UTC)