when i listen to the songs you can here the Soloists sining and at different points in the songs there are others that sing a few words then stop. from what i can gather they get singers to come in and sing a few songs when they wont to release an album the sings are not
they are asked by Integrity Music if they would like to come in and sing for a price
one one album Guy Penrod is singing he is the main singer the others are just back ground vocals that sing with him from time to time threw the song