Grouping qualifiers in the output of a Wikidata SPARQL query

Question

I am building a Wikidata SPARQL query to retrieve details about specific people. When asking for their educational details (P69 - educatedAt)- I am not sure how to craft the query such that it will collate their degrees and majors in the case that in one statement about being educated at an institution they have multiple degrees or majors (I used this other query to find people with multiple degrees from Harvard).

This is the query:

SELECT ?itemLabel (GROUP_CONCAT(DISTINCT ?altNames; SEPARATOR = ";") AS ?aliases) ?itemDesc ?genderLabel ?birthday ?placeOfBirthLabel ?image (GROUP_CONCAT(DISTINCT ?ed; SEPARATOR = "|") AS ?education) WHERE {
  VALUES ?item {
    wd:Q5402996
  }
  OPTIONAL {
    ?item skos:altLabel ?altNames.
    FILTER((LANG(?altNames)) = "en")
  }
  {
    OPTIONAL { ?item wdt:P21 ?gender. }
    OPTIONAL { ?item wdt:P569 ?birthday. }
    OPTIONAL { ?item wdt:P19 ?placeOfBirth. }
    OPTIONAL { ?item wdt:P18 ?image. }
    SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
  }
  {
    OPTIONAL {
      ?item p:P69 ?statement.
      ?statement (ps:P69/rdfs:label) ?eduLabel.
      FILTER((LANG(?eduLabel)) = "en")
      OPTIONAL { ?statement pq:P580 ?edStart. }
      OPTIONAL { ?statement pq:P582 ?edEnd. }
      OPTIONAL {
        ?statement (pq:P512/rdfs:label) ?edDegrees.
        FILTER((LANG(?edDegrees)) = "en")
      }
      OPTIONAL {
        ?statement (pq:P812/rdfs:label) ?edMajors.
        FILTER((LANG(?edMajors)) = "en")
      }
      BIND(IF(BOUND(?edStart), CONCAT("::start:", STR(YEAR(?edStart))), "") AS ?edStartText)
      BIND(IF(BOUND(?edEnd), CONCAT("::end:", STR(YEAR(?edEnd))), "") AS ?edEndText)
      BIND(IF(BOUND(?edDegrees), CONCAT("::degrees:", STR(?edDegrees)), "") AS ?edDegreeText)
      BIND(IF(BOUND(?edMajors), CONCAT("::majors:", STR(?edMajors)), "") AS ?edMajorText)
      BIND(CONCAT(?eduLabel, ?edStartText, ?edEndText, ?edDegreeText, ?edMajorText) AS ?ed)
    }
  }
  SERVICE wikibase:label {
    bd:serviceParam wikibase:language "en".
    ?item schema:description ?itemDesc.
  }
}
GROUP BY ?itemLabel ?itemDesc ?genderLabel ?birthday ?image ?placeOfBirthLabel

For the education result I get:

Harvard University::end:1980::degrees:Master of Arts::majors:astronomy|
Harvard University::end:1980::degrees:Doctor of Philosophy::majors:astronomy| 
University of Rochester::end:1976::degrees:Bachelor of Arts|
University of Rochester::end:1976::degrees:Bachelor of Science

I would like to get:

Harvard University::end:1980::degrees:Master of Arts;Doctor of Philosophy::majors:astronomy|
University of Rochester::end:1976::degrees:Bachelor of Arts:Bachelor of Science|

How can I group the degrees in line like this in my query? Or even better have them be nested in the JSON output rather than using delimiters?