haven't tried this if apps are part of different add-ons, but I don't think that works.
Otherwise you would need to build this functionality into your backend
As Nils mentioned, if your apps are in one add-on package, they can share data easily.
One thing to note here, there are two ways to put multiple apps into one add-on package.
First where all apps are part of common app.xml and hence common generated definition.json.
Other way is each app can have its own app.xml, hence own auto-generated definition.json and hence its own UUID.
In both these case the end result is still one add-on package with one extension.zio.
As far as I know, in first case the apps will be able to share data.
In second case it might not be possible due to different IDs generated.
Keep that in mind when you try this.