Here’s how the app I mentioned immediately above handles it:
Splitwise is a shared ledger for friends. Expenses you add in Splitwise are not public. Friends who are included on an expense can view that expense, and, if an expense is added in a group, other group members can view expenses shared on Splitwise. You choose who you share your expenses with and what kind of expenses you want to share. Anyone shared on an expense or in a shared group has the ability to edit, delete, and undelete the expenses that have been shared with them.
