Merge approvals two times by the same user

Hello,

We have created two user groups to accept merges request.
The group “Testing” and “Code review”.
Some users are in both groups.
Our merges request need two approvals to be merged.
We would like a user who is in the “Testing” group and in the “Code review” group to be able to validate the merge request twice. Once as a “receiver” and once as a “code review”.
How to make the same person give his approval twice?
It doesn’t seem possible.

Thanks for your help,
Have a nice day
Xavier