Hi Laura,
The change to let users implement multiple Web Properties on a single page would require core architectural changes to be made to DTM.
Also, DTM already provides efficient ways to separate out tools and other marketing tags. Hence, I do not see this change being in pipeline for DTM Product team. Please refer to the below documentation for Tools and Tags for your reference:
https://marketing.adobe.com/resources/help/en_US/dtm/tools.html
In case there is a specific scenario you have and would like help with, let us know or reach out to Adobe ClientCare with the same.
~Kaushal