AutoFill data from few columns of different table during add

How to fill additionall values from related table?
Ie: I have 2 tables - Users and post

I’d like to have such ability that when I add new post and choose user from available users, his email will also be autofill on secon field - please look at screenshots:

Add new post window:

His email should be autofill in next field:

For now Ive configured DataSource field in standard way:

Please Help
Kind regards,

create a custom endpoint to get data from the database and parametize it so you can access it by the first select option you enter! from there follow these steps

  1. create an axios get request in radsystem it looks like this
       let results =
this.loading = false
  1. you can do this in the vue js mounted method or watchers but i dont suggest watchers unless you can use lodash to check if the user has stopped typing to prevent the watchers sending a request to the database every time you type a letter
  2. finally go to the assign formData.fieldname to be equaL TO THE VALUES YOU GET FROM THE RESPONSE OF THE API
    they will get autopopulated based on the first parameter you pass to the endpoint