I want to configure bitcoin-qt to work as a 'client' for parallel bitcoind server (the same way as bitcoin-cli), but I don't see any relevant configuration options. In my PC bitcoind has folowing configuration: data directory is /var/lib/bitcoind, it is run as 'bitcoin:bitcoin' user (with the same data permissions in /var/lib/bitcoind). Running bitcoin-qt from main desktop user does not work because bitcoin data directory permission differs, running gui app from 'bitcoin' user also does not work.
I want to work sometimes with bitcoind, sometimes with bitcoin-qt. The problem with bitcoin-qt is that there are no separate bitcoind/bitcoin-cli programs. In case of bitcoind I can preserve normal 'bitcoin:bitcoin' data directory permissions and connect to bitcoind with bitcoin-cli. Bitcoin-qt documentation mentions 'rpc_connect' options, but they seem to apply to possible bitcoin-qt clients, not bitcoin-qt acting as a client to bitcoind.
Curently I see the only way to archive what I want: change data directory permissions to main user (who starts bitcoin-qt). But this method is hackish because it requres modification of systemd bitcoind.service file, data permission changes, etc, which I would like to avoid. Perhaps I am missing some way to configure bitcoin-qt properly?