Hi,
Thank you so much for your interest in our products and for using our community.
Based on the Control Register (CTRL), I understand that it is possible to generate the interrupt without the INDEX pulse initializes the position counter.
For this you must configure XIE->1, XIP->0, and XNE depending on your choice. With that the INDEX interrupt occurs when XIRQ is set.

Hope it helps you. Please let me know if you have more questions about it.
Have a nice day!