List multiple e-mail addresses in 1 cell

I inherited a spreadsheet that had a cell designated for email addresses. Some had multiple e-mail addresses listed in the cell and they show as a vertical list see column B on attachment. I can not re-create this formatting. See example below. I do not want them listed on separate lines as other columns in the spreadsheet would then be duplicated.

I tried to attach a sample, not sure if that is working either.
Thank you,