Git log three-dot notation: include merge base

If you consider a simple case where I run the following command:

$ git log --oneline --graph --decorate A...B

Where A and B are both branches with a single merge base and a series
of commits on each branch. Very simple example with no loops or crazy
ancestry. Below is an example repo I set up, where I show the whole
repository log graph:

$ git log --oneline --decorate --graph --all
* eb28ae4 (HEAD -> B) Commit 6
* 7173fa1 Commit 5
* b5fe27b Commit 4
| * 37a8ca8 (A) Commit 3
| * 72745a7 Commit 2
|/
* ffc8040 Commit 1

Using A...B notation, I get this:

$ git log --oneline --decorate --graph A...B
* eb28ae4 (HEAD -> B) Commit 6
* 7173fa1 Commit 5
* b5fe27b Commit 4
* 37a8ca8 (A) Commit 3
* 72745a7 Commit 2

The graph no longer makes any sense, and isn't helpful to me at all.
This is because the merge base commit isn't shown. I understand this
is "by-design", but is there a way to include it? It's necessary to
have it, for this graph to make sense.