Is it permissible to marry the daughter of a maternal aunt if her maternal grandmother breastfed her twice?

Scholars have differed regarding the amount of suckling that establishes prohibition (of marriage). Some said that both a little and a lot of suckling cause prohibition, and this is the madhhab of Malik, Al-Awza'i, and the Ashab Al-Ra'y (people of opinion). This is also the followed madhhab in Morocco. According to the preponderant opinion, the questioner's maternal cousin is considered a stranger to him, because two sucklings are not sufficient; rather, five sucklings are necessary. The definition of a "suckling" is determined by custom. And it is better, to avoid dispute, to abstain from (marrying) this girl who is said to have suckled from his grandmother.