Something I do, which granted is not a complete solution, is that I set my party chat color to something else (In my case orange). So in quests, while everyone is in party chat, the moment the DM says something it'll come out in white and make a big difference.
To do so, I modified these following lines in my nwnplayer.ini file
[Chat Colors]
TalkColor=240,240,240
ShoutColor=255,239,80
WhisperColor=255,15,15
TellColor=32,255,32
ServerColor=176,176,176
PartyColor=255,102,100
DMColor=16,223,255