I am looking for the best approach for merging stacked Merge Requests in Gitlab. By “stacked” I mean the following:

• MR1 that is opened from branch feature/A onto main;
• MR2 that is opened from feature/B onto feature/A;
• MR3 that is opened from feature/C onto feature/B.

As soon as I have all three merge request approved, I want to merge them at once. What is the best possible approach for this scenario? How am I supposed to merge this Merge Requests via web UI? Consider the “Delete branch on merge” and “Squash commits on merge” features to be enabled.

I have tried to merge feature/C into main locally and then push the updated main branch to the remote repository. However, that resulted into MR1 was automatically closed, but the MR2 and MR3 remained opened in the repository.