How to know the connector:ids for indoor OSM (vertical passage)?

Hi all, we currently are modelling an indoor osm map following the Indoor Schema. There is also a part in which vertical passages are described. It connects the doors of elevators, stairs and others with the doors above and below it. That means you have to know the doors' ids of both "neighboring" doors. The connection is done by the tag connector:ids:

      <node id='-245' action='modify' visible='true' lat='52.39349018473089' lon='13.130163004646104'>
      <tag k='connector:ids' v='<id_door_above>, <id_door_below>' />
      <tag k='door' v='yes' />
   </node>

We model our buildings in JOSM. JOSM gives negative IDs to each new element and those IDs will be replaced by positive ones when the data gets uploads. The IDs in the tag (written by hand) won't be replaced which makes the file inconsistent. (Though I cannot verify at the moment because currently I'm not allowed to upload any indoor data for legal reasons).

A solution would be to upload the floors one after the other, but to me it doesn't seem to be a good solution.

Has anyone ever run into this problem? Have I missed to read the best practice?

Thank you for your time and any help!