Hi!
I'm building a Power Apps Canvas application. I have a Dataverse tables Tasks and Assigned Tasks (one Task may have multiple related Assigned Tasks with different Assignee column value).

In the canvas app I have a drop down of Users.
The goal is to show a gallery with list of Tasks which satisfy the following condtion: there are no Assigned Tasks related to the Task and assigned to the selected User. So basically it is the list of available Not Assigned Tasks for a particular person (not current user in general case).
E.g. I have Task 1 without Assigned Tasks, Task 2 assigned to User A, Task 3 assigned to User B, Tasks 4 assigned to User A and to User B. Then:
- If User A is selected in the dropdown, then gallery shows Task 1 and Task 3.
- If User B is selected in the dropdown, then gallery shows Task 1 and Task 2.
- If User C is selected in the dropdown, then gallery shows Task 1, Task 2, Task 3 and Task 4.
I don't get how to achieve this using View or Filter function without using intermediate collections. The query has to be delegated to Dataverse.