1. Open iTunes and go to your music library.
2. Select the albums you want to merge. To select multiple albums, hold down the Command key (⌘) while clicking on each album.
3. Right-click on one of the selected albums and select "Get Info" from the menu.
4. Click on the "Album" tab in the info window.
5. In the "Album Artist" field, enter the name of the album artist for the merged album.
6. In the "Album" field, enter the name of the merged album.
7. Click on the "OK" button to save the changes.
The selected albums will now be merged into a single album in iTunes.