You can create and schedule listings to an advance date and/or time. Then, when you have assembled a group, you can stagger the actual "go live" dates and times. If you select a single time for all, the actual listings will start somewhere within the same minute -- usually between 5 and 15 seconds apart.
When I relist from the Unsold section, I always use the bulk editor and select a time range. For example, I may start with tonight at 7:07 p.m. and space several more relists at 37-minute intervals.
~~C~~
My Glass Duchess
Quoting Mom: In polite society, "hey" is for horses.