[chipf0rk]

Alright, I was able to do this, found this info:

In an orange box update the var mp_ignore_round_win_conditions was added, you have to set it to 1 so that the round never ends. Yes, also when one team is completely dead. But be aware that never means never, I've read that apparently the round doesn't even restart when the roundtime ends with that variable set to 1.
But that doesn't really matter for my DM server.