A common complaint is that in case of samplers you have as many albums as there are artist.

JRiver thinks an album is an album if Album and Album Artist are the same.
The answer is obvious, if you want to display a sampler as one album see to it that the Album Artist is the same for all tracks.
1- Select the entire album by e.g. typing is name in the search box

2- Select them all (CTRL/A) and choose file to display all tracks in the files panel

3- To preserve the individual artist, select all tracks and type =[album artist] in the Artist field.

4- Change the Album Artist to Various Artist or any other text you prefer.

Now you have one album in the interface.
Often rippers use a rule like /[artist]/[album]/ as a naming convention for the directory.
As you have different artist, this will split the album.

Most of the time you discover this after the rip has been done.
You can re-rip but there is a very elegant solution in JRiver.
1- Select all the tracks and choose Library Tools > Rename, Move & Copy files
2- Apply a rule like [Album Artist]\[ALbum]

Now you have all the tracks in one directory with the name of the album.
