How to cycle an aray to the beginning when the end is reached multiple times

[McGeoffrey Kutor]

I have multiple two column arrays "SLOT_NO" and "SLOT_MONTH_ARRAY". Using the lead function, I am able to run the arrays (In a cross table) in a forecast from 1 to the end being 12 but I am having problen restarting from the beginning when the end is reached. The end of the first cycle is determined when last "SLOT_NO" equals the last"SLOT_MONTH_ARRAY". The column "NEXT_PM_SLOT" determins which position to start from in a next cycle order. Some arrays are just 6 rows deep instead od 12 rows deep. Can anyone help