public OnPluginStart()
{
    HookEvent("round_start", RoundStart, EventHookMode_Post)
    HookEvent("round_end", RoundEnd, EventHookMode_Post)
}

public Action:RoundStart(Handle:event, const String:name[], bool:dontBroadcast)
{
    ServerCommand("exec round_start.cfg");
}

public Action:RoundEnd(Handle:event, const String:name[], bool:dontBroadcast)
{
    ServerCommand("exec round_end.cfg");
}