non avrebbero [..] motivato in merito al fatto

Italian to English Law/Patents Law (general) Court ruling

Hi, I'm confused by this legal phrase in the ruling of the Supreme Court of Appeal (commenting on rulings by two other courts):

Secondo la Cassazione, i giudici di merito non avrebbero sufficientemente motivato in merito al fatto che le transazioni stipulate tra X e Y riguardassero tutti i rapporti di dare ed avere tra le parti.
My attempt is:

According to the Supreme Court of Appeal, the courts dealing with the case had not "sufficiently proved the grounds for the fact that" [doesn't sound good!] the transactions entered into between X and Y related to all the debtor and credit relationships between the parties.
Thanks for any help.