In most cases, one Hymn is enough for Communion, especially as in most cases there will be one or more "Special Ministers" to help distribute communion.
You are welcome to choose an additional Communion Hymn just in case, which I will perform if needed. However please note that there is a high likelihood that the second Hymn will not be required, therefore I would strongly recommend you do not print this in your booklets.
Alternatively I will play some christian instrumental music which can be faded out when needed. If booked with a live pianist, the pianist will fill out any remaining time with appropriate piano instrumental.