What do you mean by the ‘Tasks connected to it’?
Based on how you have described your relations
a Task could be linked directly to a Meeting (many-to-many), but can also be inferred as being related to a Meeting because it shares the same parent Project.
If you want to show the Tasks indirectly related to the Meeting, you could create a lookup, but this would be a read-only field.
The Tasks field you are showing in the image above represents the direct relation by default.
If you want to change the relation view to be context filtered to show indirectly related Tasks (= those Tasks owned by the Project that the Meeting is owned by) then it is not possible for the reasons explained here: