From your description, the only way I can think of to do what you're asking is to use "buckets" which is a PITA to do if you have a lot of records. Since you've not presented a screen capture and its still a bit unclear to me how your records are sorted, it sounds as though they look something like the following:
ParentId ParentName Related Record Id Related Record Name
Some Id John Some Diff Id John, Joe or even Mary
To make your bucketing easier, you might want to create a compound formula field Called ReportGroup
where it's value =
Record Id & Record Name
and use that to do your bucketing with. You'd then more easily be able to tell if you had the both the same Record Id
and Record Name
that you wanted to group and assign an Alias of some to the selected records; after which you could hide the formula field from being displayed. Unfortunately, I believe you'd would need to add this field to your database.