combine a subset of elements in 2 JSON objects into a third using VB.NET

I have two JSON objects that are pulled from a URL's and want a separate JSON object built using efficient VB.net code that includes only the some of elements :

https://icite.od.nih.gov/api/pubs?pmids=28968381,28324054,23843509

Output will include linked by pmid to uid

pmid
year
is_research_article
relative_citation_ratio
nih_percentile
is_clinical
citation_count



https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi?db=pubmed&retmode=json&id=28968381,28324054,23843509

Output will include linked by uid to pmid

uid
pubdate
epubdate
source
authors in a concatuaded string in order ie "Hutchins BI, Klenke U, Wray S"
volume
issue
pages
issn
essn
pubtype
fulljourbalname
sortpubdate

Please don't low bid and have me talk for awhile and then say you need more money. Bid what you feel it's worth. Describe to me your process. I already have code that will create a class and then sterilize it into an object.
Dim jsonString = JsonConvert.SerializeObject(output)

I need fast code. If you can build the class efficiently then I'm interested. but to build it once and then loop it every time till you find a match then add and then loop. I need better.