Preferential Voting with Concensus Rules
Description: You (the election coordinator) choose the options to vote on.
The voters then preferences these options in order from 1 to 'n' in order of priority (where 'n' is the total number of options available).
A number 1 indicates a primary preference (the most prefered).
The counting process involves Eliminating and Electing (if more than one option is to be chosen) options using a Quota (proportion of total votes).
This is derivation on Preferenctial Voting.
The addtion of concensus rules means that if enough voters "block" concensus on an option, then this option is treated as "eliminated" at the start of the count, and it is then redistributed to its next valid preference.
Commentary: There are very few instances of concensus being associated with the STV systems. I have added it here more as an example.
History: The NSW Greens Party in Australia uses a Concensus form of Preferential Proportional Representation in choosing it candidates.