Custom trigger sequences is the way to go when you need to trigger cameras at specific time. With this module, you can create your own trigger recipes in advance either directly in Xangle or using Excel
In the example below, I'm using 12 cameras and 3 shots. The first shot is the "A" column, and I want to trigger the cameras 1,2,3,4 at 0ms, then 5,6,7,8 at 50ms and 9,10,11,12 at 100ms. Then at 2000ms and 6000ms, a second and third shots are taken with all cameras.
This is my Excel spreadsheet:
To get these values in Xangle, select all 12 rows + 3 columns from Excel, copy the values (ctrl-c), open the Custom Sequences module in Xangle, and simply paste (ctrl-v) from any cells.