Create complex filter on members from 2 dimensions

Question

Hello all,
I have an ASO application having 15+ dimensions. 2 of them say (D1 and D2) have members that are tagged with same UDA (myUDA). The UDA indicates access level granted to that member. I want to make sure that, user gets access only when both members from D1 and D2 have UDA.
In case that either of members from D1 or D2 do not have this UDA assigned, user should see NO_ACCESS.
What is the best way to write this filter?
I've tried following but it works incorrectly.
Filter: test
None: IDESCENDANTS("D1")
None: IDESCENDANTS("D2")
Read: @UDA("D1","myUDA"),@UDA("D2","myUDA")
With above specification, any member of D1 and any member of D2 having UDA "myUDA" currently has access to data. Please note that, number of members having UDA "myUDA" assigned to them runs in thousands.
Thank you.

Answer 1

Hello Hyperion19M,
Thank you for your time and suggestion. I've tried filter as you've suggested. In my case, not all members of D1/D2 have 'myUDA'. Hence, the combinations that get created are:
(all members of D1 having 'myUDA') x (all members of D2 having 'myUDA'). I only want the actual pairs that should have the access.
I've tried this way now and it is working for me (for now):
Filter: test
Read: (member 1 of D1 with myUDA),@LIST(member of D2 with myUDA associated with member 1 of D1)
Read: (member 2 of D1 with myUDA),@LIST(member of D2 with myUDA associated with member 2 of D1)
...and so on.
So, I'm specifying as many number of 'Read' = No. of members of D1 with 'myUDA'. I am not sure, if this will hit performance, but so far it's working well for ~3000 such members.