Two sites, same database?

I believe this question (or similar) has shown up before…

I have a ‘main’ WP site with all the bells and whistles and I would like now to create a second site -with a different design theme- much lighter and only showing certain post categories from the main site. I’d prefer to have only one site to maintain as the second would be merely “reading” from the first one (no interaction, no comments from readers). If you will, the second site would be like a mini-first site (or a summary of it).

I’ve read that two sites on one database is not possible because the domain name is somehow embedded in the database, and also that Google would penalize such arrangement.

Any ideas out there that could help me to achieve such objective WITHOUT any programming?… and without Google penalizing me of course!

Thanks a lot for any viable suggestion (or any reasonable explanation discouraging me to try it).