I found some information that might be interesting for you. In 2011 the cementery in Holszany was cleaned by the students, they created a list of buried people (see page 6), here is link to the pdf https://hist. bsu.by/images/stories/files/radavod/galshany.pdf. There are a few Gan surnames here, see records 57-60 on the page 10.
2020-08-12 Марына Дайнека