Hi @Oliver_Hambrecht,
hi @Philip_Mathew,
Thank you for your active participation in our forum and this thread.
Currently, in the combination print, it is not possible to explicitly address TOC or IDX, as these have always been handled internally. However, for the upcoming product version, we are planning several enhancements in the area of combination printing. This will include triggering the NextCombinationPrintStep event for these report sections. This specific request has already been documented here in Idea Place Improvements to Combination Print - feel free to vote. 
Regards,
Daniel