Docker-compose internal network without swarm

Hi,

I want to create an internal network, that doesn’t use bridge mode. Containers in this network should be able to talk to each other but no IP connection to the host/outside should be established.
When using “internal: true” in the compose file this seems to be ignored.
I use compose file version 3.

Can this be realised this without using swarm or another additional technology?

Thank you