Flatten a one to many relationship result in a query

[JELLA]

I have a one to many relationship that results in
duplicating values in a query for each parameter defined
by the relationship. Is there a way to flatten or 'roll'
this up? For example a query that joins a car models
table to a car colours table repeats the all the car
models for each different colour value. Is there a way to
flatten the query so that for each unique car model, the
colour field is comma delimated?

I have been puzzled by this problem for months - and I'm
sure there must be a simple answer.

Thank you for your kind help
JP