(some) users do something at event

Scenario: club hosts an event
Certain parts of the event are at a member’s home (ex: visit house, visit garden)
Other events are not hosted at a member’s place but in the street (ex. marching band)
Some members don’t participate in this event, the number of participants varies.

Given that users 3 & 4 don’t participate, I would like to produce a list like this:
Participating users:
User1: does this
User2: does that
User5: something else
In the street: marching band, hot dogs and what have you

I can produce a list ( a table if you will) of participating users through a multiselect CCK Userreference field, but this only gives a list of users, not the part ot the event that’s taking place, like so (the ‘does this’ part is missing):
Participating users (label)
User1(userreference)
User2(userreference)
User5(userreference)
does this
does that
does something else
In the street(label): (field content)marching band, hot dogs and what have you

I basically need a field that is a label (‘userfield’) and a field has content (‘does this’), but as the number of participants varies, I don’t see how I could get the input interface that I need ('Add new field for every participant').
Any ideas? Thanks.