[Need advice] Biter advancement, teams on different forces

[Wezz]

We are a small group of friends playing coop on a dedi server. We like to play on different teams since it makes it harder when you have your own research.

The problem is that not everyone is online at the same time and the other players won't know if the biters go to attack on the player which is offline.

It's of course possible to shut down the power when you go offline, preventing the pollution to attract biters. But it won't help with the new bases the biters advance with now and then. Yes it's possible to disable that feature but we want it enabled.


I'm hoping you could give us some useful advices regarding this issue.

Possible solutions/workarounds:
-Everyone build radars together at certain locations (this will show attacking biters but won't notify you)
-Some kind of alarm system with wires?
-Everyone build cheap turrets together around everyone's base
-Possible mod for this?

How are you managing in these situations?