Need help with Xiaomi open rule

I have a rule, if i´m opening a door, amazon echo says that is open.

rule "Balkonvoiceoffen"
when
    Item xiaomi_balkon changed to OPEN
then
    Echo_Diele_Room_TTS.sendCommand('Balkontuer offen')
end

but now I also need
when xiaomi_balkon is still open, and xiaomi_eingangstuer is opened
then
Echo_Diele_Room_TTS.sendCommand(‘Achtung! Balkontuer ist noch offen’)

Nice to have would be a check of all sensors, when s.o. wants to leave the house.

Is that possible?

You can’t do that, the when clause is about events, not steady states.

You can rephrase your requirement though -

when
xiaomi_eingangstuer is opened
then
if xiaomi_balkon is still open, do stuff