Where can I find MBA summer internships?

I'm a first-year MBA student at one of the top schools outside M7. I have a previous buy-side equity research experience outside the U.S, and now I'm looking for summer internship in HF/AM equity research. I've interviewed with five AM+HF so far, but I haven't secured an internship yet. I knew this was going to be a uphill battle before coming to MBA, but this is even more frustrating than I expected.

Now the biggest challenge is how do I find which firms are hiring MBA interns? It seems like the ones that are hiring rarely post the jobs on their career webpage, and often times their websites (HF) have a single page with absolutely no information about anything.

Is there any good place to find which firms are hiring MBA interns and which firms have hired in the past?