Fabian,
Yes this can be done. Take a look at the screenshot in this comment. You can have multiple WLANs with different name however with same ESSID. Each unique ESSID can support different or same config which is ur need and its the ESSID which gets broadcasted in the air
One use case where i used this was one controller in building X where users get IP from VLAN 10 however this controller also supported users in a different building which had a different VLAN scheme so default ZD behaviour was NOT suitable and customer was NOT keen on Dynamic VLAN as they did not wanted to complicate the matter further..
this worked for them and i think this should also work for you if my understanding was correct of your issue..