I've made this command

execute @p ~ ~ ~ detect ~ ~-1 ~ minecraft:diamond_block 0 spawnpoint @p'

and I want to make it so that it won't detect the nearest player; rather, it will detect whoever is on the diamond block. The problem with this command is that whoever is near the command block receives the target and I want it to target the player on the diamond block. Is there any way to do this?