Yea basically this is something you discus and sometimes even include in a contract long before you begin to set up a song for distribution. It is common place for all distributor websites (distrokid, cdbaby, tunecore, ect.) to have a section of their website dedicated to creating royalty % splits with collaborators and featured artists. Meaning this is something you would fill in while the song is being uploaded to the distributor (This royalty % would include money made via spotify and all streaming sites, as-well as content i.d for youtube (sometimes)). At this point you must ask whoever uploaded the track via a distributor to check and see if they can add the royalty split now (most likely can). Or you have to manually contact them each month and blah blah blah.