Run PoS coin with masternode having more than one node?

Hello,

I hope this is the right place for generic question regarding running a PoS coin masternode with more than one "node" in masternode.conf. I've tried with Nyxcoin - but after some research this seems to be a generic question/problem at all?
I had running a single masternode/wallet fine for month. I tried to add another node by adding additional IP address and second genkey, tx-hash/output into masternode.conf.

At first it looks like working fine. In my case I was able to fetch node-status'es by using API-Command "masternode list-conf". First node went to ENABLED very quick. Second node (using different IP!) struggles between PRE_ENABLED and WATCHDOG_EXPIRED.

I left it running some days - even tried restarting the daemon and so on without getting ENABLED state for second masternode. Generally I suppose it should be possible. The debug.log also mentions second masternode-ip broadcasting as well. And even the API-Commands "suggest" it should be possible by commands like masternode start-all" or "start-many" which implies there could be more than one node in a single wallet.

Does anyone have an idea? Alternatively is it possible anyhow to "share" blockchain-data" between two wallet/node instances to avoid having two separate directories consuming double space for same data (which can become a few GBs for coins that succeed for some years ...).