Avoid completing directory names when changing vim buffers

Suppose I have a directory structure, such as

dir
├── foo
│   ├── bar.c
│   ├── bar.h
│   ├── foo.c
│   └── foo.h
└── config
    └── foo.conf

And I have each of the files in foo/, as well as foo.conf open in a vim buffer. If I want to switch to foo.c, I type :b foo<TAB>. However, since “foo” matches the name of the parent directory, vim suggests all the files in foo/ as possible matches.

I would like only foo.conf,foo.c and foo.h to be suggested. Is this possible in any way?