The cascading is slightly different with the collections, but follows a similar trend.

https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/Cascading-Behavior-for-the-Autodesk-Industry-Collections.html

Essentially, a product will look for the cheapest available license first so to speak. So, a subscription of a single product, followed by an older style perpetual license. After that, it will look at the collections, before looking at the suites. The difficulty is getting the license manager to identify which collection license it should use first. The simplest way to get around this is to ensure that all issue dates in the license file match, then put your products in an order within the license file which suits the way you would like them to cascade.

For example, if you had AutoCAD product licenses, alongside both an AEC Collection and PDM Collection you could order the license file in such a way that the AutoCAD license would be taken first by an AutoCAD user, followed by the AEC Collection, and lastly a PDM Collection. In other words, place your products in the order in which you want them to cascade. This won’t stop the product opening a single product license file, but can control the cascade between collections.

e.g.

SERVER SERVERNAME SERVERMAC
USE_SERVER
VENDOR adskflex port=2080
PACKAGE AUTOCAD_X_X adskflex 1.000 \
XXXXXXXXXX
ISSUED=01-Aug-2018 \
XXXXXXXXXX
XXXXXXXXXX
INCREMENT XXXXXXXXXX 18-jan-2020 5 \
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
PACKAGE AECCollection_X_X adskflex 1.000 \
XXXXXXXXXX
ISSUED=01-Aug-2018 \
XXXXXXXXXX
XXXXXXXXXX
INCREMENT XXXXXXXXXX 18-jan-2020 5 \
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
PACKAGE PDMCollection_X_X adskflex 1.000 \
XXXXXXXXXX
ISSUED=01-Aug-2018 \
XXXXXXXXXX
XXXXXXXXXX
INCREMENT XXXXXXXXXX 18-jan-2020 5 \
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX

So to solve the issue:

The best option you have is actually to use an Options File, where you would instead of relying on cascading licenses, control which licenses you wish certain users or groups to have access to:
https://knowledge.autodesk.com/customer-service/network-license-administration/managing-network-licenses/controlling-license-usage/control-network-license-access-using-options-file