Limit users ability to view reports - dashboard access only

Within our organisation I have created various dashboards and given relevant users access to certain dashboards, not everyone has access to all of them. I thought this was all working well however I have just discovered that by clicking on any visual in the dashbaord the user gets access to EVERY page and visual in my report(!). 

No, I will first of admit that this has been caused by a lack of thorough due dilligence by me however I am quite suprised. 

Is there anyway that I can limit this. Once I have provided people with dashboards I only want them to view report pages containing those visuals, or even more drastically, not allow them to view the report at all.

On a side note, how would I create multiple reports without having to rebuild my entire data set for each report? Currently I have one data set which is linked to a single PBX file.  I make import all my data via this, create measures, make visuals etc and then publish to PowerBI in a report (and dataset) called "Company Data". 

Is there a way I can create multiple reports without having to build a wholoe new data set each time which would be a mess to maintain. 

Thanks.