You create e.g. 3 branches in SVN:
All developers have access to trunk. The release managers have access to testing and stable.
Changes from trunk were merged (applied) to testing and if they work you can merge them to stable.
You can then export the revisions from testing and stable to the webservers with svn export command.
To get a easy way to switch back to a old revision later in case that somethin does not work in stable, then you can create a tag for every released version, so its easy to get back to that version.