Workaround for parameters, that can be set only once in system while creating tests in Selenium Webdriver

I have little problem with creating functional tests in my application. In this app we have few parameters that can be set only once, after setting it i cannot turn of new functionality. The main problem is that before turning on this parameter on interface some of processes may work different, than after checking it. Notice, that there is few parameters like this, so i have big problem with creating tests that must check every single configuration of this parameters.

Also there is one more condition for my test framework, that there must be at least 4 tests that are running in the same time (parallelism), so even if i solve problem with making good order of tests or making some backups/snapshots of database in choosen moments there is a chance, that tests may start restoring database to choosen moment while another tests is running or working on specified configuration.

Did anyone of you faced with problem like that? Any suggestions that may give me a little help will be appreciated.

Regards.