Dear Dr. Eschrich,
My name is Darina Yordanova and I would be happy to assist you.
This functionality is not available in Toolbox v.4.x.
Possible workaround to group chemicals according to their similarity is to use the clustering functionality.
In order to do this, you should:
1) load both lists(inventories) of structures on the data matrix.
2) go to the Category definition module and click on the Combine button and select the lists. You will see two options: AND will identify the chemicals which are common for both lists; and OR - which will create a new list with all unique structures from both lists. Select the "OR" option (Fig. 1)
3) Once the new list is created, select the Structure similarity profiler and then click on the Clustering button (Fig. 2)
4) You can change the similarity options or to keep the default. When confirm the similarity settings (click on OK), you can define the similarity threshold (Fig. 3).
Based on the selected similarity settings and the specified threshold, the chemicals in the list will be split into different clusters.
Hope this is of help.
Many thanks Darina - this workaround helps/solves my problem!