Poezio does not support multi-accounts, and we do not plan to do so in a foreseeable future. However, you can run several poezio instances (e.g. with tmux or screen) to have similar functionnality.
You can specify a different configuration file than the default with:
./launch.sh -f separate_config.cfg
The relevant options for a separate config are the following:
Those options are detailed in the configuration page.