Count participants

[Simon Hall]

In my library 'Pub Visits' I have Link to Entry field called 'Participants (Individual)' which links to library 'Participants' which is just a list of names with a field called 'Name' to use

I would like to create a field in library 'Participants' which shows the number of times each 'Name' appears in library 'Pub Visits' but really don't know where to start.

If the answer involves JS could you please provide some code for me to try. Thanks