Create a third JSON files from data in 2 JSON files using vb.net

I have 2 JSON files that are attachments [login to view URL] has "YEAR":"ISSN": and [login to view URL] has "YEAR": "ISSN": "IMPACT The [login to view URL] file has over 10,000 rows the [login to view URL] has less than 200. I need a third json file that has YEAR, ISSN, IMPACT only for the items on the [login to view URL] file. be careful the ISSN has duplicated based upon the year. So it only unique based upon ISSN and YEAR. I would like it done without a loop. I can't see looping a 10,000 item object 100's and 100's of times. Using [login to view URL] is fine. I need the fastest execution possible since this will be used in a live web app. In the past I've stored the IMPACT data in a SQL database and passed in a JSON object of the YEAR and ISSN numbers that were wanted and did a JSON join of the data, which worked great but I'm trying to get away from the MS SQL Database