This idea wa sposted 2020 and has 79 upvotes - is it possible to get a status from Hubspot on where this fits to your roadmap?
We are struggeling big time with this, as the only possibility today is be restricting on the user side (as mentioned in the original idea). However, user groups are also connected to reporting, and these 2 dont always match. Quite often we have sensitive customers we only need to make available to certain users, and hide from all the rest.
This segmentation is available in other functionality (properties, reports), so I can imagine it would not be a huge thing to implement. To be able to navigate to a specific contact/company and restrict specifically that this object is only to be seen by x team or x person.