I've moved your question to the scripting forum. IF this is possible, I would say it would be through the use of vertical rules combined with regular paragraph rules above and below. There is at least one script that will do vertical rules, as I recall, but I don't know if it can do both left and right.
The folks here will know.
I'd be willing to pay a fee for this solution if necessary.
¿Has encontrado alguna solución? Tengo el mismo problema y no sé como hacerlo
No, sorry not yet. Someone contacted me privately to write a script for $450US, but my company is too small to afford that currently.
The search continues!
$450 is a pretty outrageous sum, considering a simple Google search turned up DTP Utils' Paragraph Border (DTP Utils | Products | Paragraph Border), which is (1) a plug-in (that is, no script required; you add the border as a proper paragraph attribute), and (2) it's only $60.
Four other, also scriptless, ways are in Mike Rankin's Five Ways to Box a Paragraph in InDesign | CreativePro.com (found through http://indesignsecrets.com/week-indesign-articles-number-130.php). At least you can check if you really need a script.
@Jongware: There's a big difference between buying an off-the-shelf
plugin and ordering a customized script.
Consider that the plugin sells say 300 copies -- 300 × 60 = $18000
(possibly many more if it's successful).
However, clearly if there's a plugin available at $60 that does the
trick, why order a custom script?
Initial testing seems to indicate that this is indeed the solution I needed. I didn't do an Internet search because I (foolishly?) thought it would be more productive to go to the software developer's helpdesk first. They assured me it was something that needed to be done with a script, thus this post here.
Thanks to everyone who responded!
Ariel, rest assured it wasn't the price for a custom script I was objecting to. I'm sure you have more experience with that than me (considering my one and only commercial script took 6 months for creating a working concept only -- $450 would not be enough to cover those costs!). A fully custom job, plug-in or script, can be very expensive, and maintaining and updating it can be time consuming as well.
Karaczun: there are some major differences between scripts and plug-ins I need to mention. The same script can run, by and large, on both Mac and PC versions of InDesign, and with some luck on different versions of InDesign as well. Also, it has no influence at all on the document itself -- this can still be opened and edited without having the script installed.
A plug-in, on the other hand, works only on (a) a certain version of InDesign (you need different versions of the plug-in for different versions of ID), and (b) a certain platform (you need a Mac OS version or a Windows version). Also, depending on how the plug-in operates, it may be impossible to edit or even open the document on computers without the plug-in.
Me he descargado la demo y estoy muy contenta con el resultado me va ahorrar muchas horas de trabajo, lo que si encuetro una deficiencia y es que cuando el estilo de párrafo contiene una tabla o una imagen anclada este no se sombrea. Me he puesto en contacto con el creador a ver si hay alguna manera de hacerlo de ser así estaría más que agradecida ya que los libros con los que trabajo contienen infinidad de ellos.
Muchas Gracias a todos!!