I wrote a letter to Ladik about my project and he replied immediately!
Here is his response:

”To make such thing properly (and in precise tune), you´ll need something like "starting CV" and "ending CV" (source CV in the beginning and target CV as the end value, both quite precise).
Imagine sequencer with three CV outputs (or three seqencers) controlling notes of your your chords (advancing sequence). For slow transisiton between notes you can use an slew limiter (lag processor).
Envelopes are not usualy made to be "in tune" (no precise voltage output useful for tuning purposes) because they are usualy used for tweaking filter (it does not to be in precise tune) and opening/closing VCA.”

The same solution as Ronin proposed :-)