SPARQL output from two different subclasses - sparql

Question

I would like to include the National Party and the EU Party Group of the Speaker in the output, as well as their committee membership at the time of the respective speech.
Data Model
LinkedOpenData I am working with
When I just include the institution (here: ?party), it duplicates the speech for all the positions the speaker has ever had during his/her time in Parliament, rather than the current Committee Position. Furthermore, I have only managed to either get the National Party or the EU Party Group so far (see code below) but not both.
I would be glad for your help.
SELECT ?name ?gender ?partyname ?countryname ?date ?speechnr ?text
WHERE {
?speech lpv:spokenText ?text.
?speech lpv:spokenAs ?function.
?function lpv:institution ?party.
?party rdf:type lpv:NationalParty.
?party rdfs:label ?partyname.
?speech lpv:docno ?speechnr.
?speech dcterms:date ?date.
?speech lpv:speaker ?speaker.
?speaker lpv:name ?name.
?speaker lpv:gender ?gender.
?speaker lpv:countryOfRepresentation ?country.
?country rdfs:label ?countryname.
FILTER ( ?date >= "1999-07-20"^^xsd:date && ?date <= "2004-07-19"^^xsd:date )
FILTER(langMatches(lang(?text), "en"))
FILTER(CONTAINS(?text, 'domestic abuse') || CONTAINS(?text, 'domestic violence') || CONTAINS(?text, 'intimate partner violence') || CONTAINS(?text, 'rape') || CONTAINS(?text, 'sexual violence') || CONTAINS(?text, 'sexual assault') || CONTAINS(?text, 'gender base violence') || CONTAINS(?text, 'gender-based violence') || CONTAINS(?text, 'violence against women') || CONTAINS(?text, 'femicide') || CONTAINS(?text, 'witch-hunting death') || CONTAINS(?text, 'femicide-suicide') || CONTAINS(?text, 'excess female mortality'))
} ORDER BY ?date ?speechnr