omxplayer-wrapper is a project to control OMXPlayer from python over dbus.
You can read the docs at python-omxplayer-wrapper.rtfd.org
You need to make sure each player has a separate DBus name like so:
player1 = OMXPlayer(file_1,
dbus_name='org.mpris.MediaPlayer2.omxplayer1')
player2 = OMXPlayer(file_2,
dbus_name='org.mpris.MediaPlayer2.omxplayer2')