How to keep a custom map visible during a regular google maps search?

Question

I have a custom map saved. On the computer, I view it by going to [Hamburger Icon] > Your places > Maps. When I click on the map, I can see the places on that map. But I want to search hotels near some of those places, and I can't figure out how. When I hit the back arrow, the map disappears. How can I keep my custom map visible during a normal Goole maps search? Surely this has to be possible...