How to compare value to any values (multiple values/items)?

I have the values and keys. The values are pointing on keys.

I need to filter values which are pointing on the any key in my list. But none of the following methods works ((

Is it possible to do it?

Reproduce the three expressions from the issue in a minimal MSBuild project using the shown Key and Val ItemGroups. Start by checking the documented item-function and metadata-condition behavior; done means establishing whether filtering against multiple Key items is supported and clearly defining the required behavior or limitation.

Written by the indexing model from the issue text.