It's actually very profound. It's talking about the Holy Gifts being dispersed among the Holy, being themselves Holy and making the recipients Holy (Holy gifts for the Holy), and yet the Holiness is one, the Holiness of God Himself. So it's like a profound mystical ONE and the MANY contrast.
Basically it's talking about how God's Holiness spreads among the faithful and yet remains His own singular Holiness. It's a way of characterizing sanctifying grace, which is the life of God Himself in the soul.
It's a fitting way to describe sanctifying grace being spread out among the faithful in Holy Communion, because Holy Communion is also both ONE and MANY. In being distributed into wafers, it's dispersed among the many, but it remains the ONE Body (Blood, Soul, and Divinity) of Christ. There are not many Bodies of Christ in the consecrated hosts given to the faithful. Similarly, the sanctifying grace it brings is scattered among many souls, but it remains one sanctifying grace, the holiness of God Himself.