How to compare individuals through two paths in SHACL?

Question

This questions is related to the one at this link. Let's say it is an "extended question".

The ontology at that link contains the following individuals:

:a rdf:type :Approve ;
   :has-theme :r1,:r2 .

:r1 rdf:type :Result ;
    :come-from :m1 .

:r2 rdf:type :Result ;
    :come-from :m2 .

:m1 rdf:type :Man .
:m2 rdf:type :Machine .

Now I have added the following triples to the ontology:

:a :has-agent :x .
:m1 :friend-of :x .

That is: ":x is the agent of the Approve action :a" and ":m1 is friend of :x".

In the question at the link above, I wanted to write a SHACL rule stating that "Every Approve action having among its themes at least a Result that comes from a Man is Legal".

And Holger suggested me to use the following condition (antecedent) of the SHACL rule. The condition works (thanks Holger!):

    :conditionTest
        rdf:type sh:NodeShape ;
        sh:property [
            sh:path (ontology:has-theme ontology:come-from) ;
            sh:qualifiedMinCount 1 ;
            sh:qualifiedValueShape [
                sh:class ontology:Man ;
            ]
        ] .

Now I want to extend the conditions above fit to obtain the following extended SHACL rule: "Every Approve action having among its themes at least a Result that comes from a Man who is friend of the Approve action's agent is Legal".

Basically: I want to start from the Approve action ":a", take its agent from one path, take the friends of the men producing results as theme of ":a" from another path... and compare the pairs of individuals through these paths, i.e., asking them when they match.

I tried to extend the :conditionTest above in several ways, e.g., with sh:equals:

    :conditionTest
        rdf:type sh:NodeShape ;
        sh:property [
            sh:path (ontology:has-theme ontology:come-from) ;
            sh:qualifiedMinCount 1 ;
            sh:qualifiedValueShape [
                sh:class ontology:Man ;
                sh:property [
                    sh:path ontology:friend-of;
                    sh:equals [sh:property [sh:path (sh:this ontology:has-agent)]]
                ]
            ]
        ] .

But no solution I tried works. On the other hand, if I use sh:hasValue and I explicitly mention the individual :x, i.e.:

    :conditionTest
        rdf:type sh:NodeShape ;
        sh:property [
            sh:path (ontology:has-theme ontology:come-from) ;
            sh:qualifiedMinCount 1 ;
            sh:qualifiedValueShape [
                sh:class ontology:Man ;
                sh:property [
                    sh:path ontology:friend-of;
                    sh:hasValue ontology:x
                ]
            ]
        ] .

It works. But this is not actually what I want: a want a SHACL rule that works for any individual as has-agent of :a. In other words: I want to get&compare this individual through the path "(sh:this has-agent)".

Hope any of you knows a way to do it. Thanks in advance. Livio