Do you still get results or not at all?
What you exactly described is not possible. Unfortunately there is no way to determine which keyword belongs to which custom field. One of the custom fields hold the 'practice, the other one the 'city'. So one of the words must had to match one field, and the other one the other field, and each word must have at least one match. It sounds easy enough, however the current architecture of the plugin and the wordpress database makes it impossible.
I'm currently writing the documentation to the next version, which is ready to get deployed. This version includes creation of fields related to custom fields: https://i.imgur.com/PYoWDZJ.png
As you can see on the screenshot, you will be able to create radio boxes, dropdowns, checkboxes, range sliders that are connected to custom field values. In your case you will be able to make a dropdown field that contains the cities or practices (or 2 dropdowns with both).Best,
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