Count Of Repeated Data

I have a spreadsheet (>10,000 rows) with data referring to a grid cell map. Each grid cell on the map has an ID and associated data. About 10% of the grid cells have duplicate records, but with different data. I need to produce a spreadsheet with a single record for each grid cell that contains the data from each of the duplicate grid cells. Some occurrences may be >2. Example below.

Current
[TABLE]Grid#;Data
1;a
1;c
2;b
3;a
4;b
4;c
5;d
5;d
5;f
[/TABLE]

Needed
[TABLE]
Grid#;Data1;Data2;Data3
1;a;c
2;b
3;a
4;b;c
5;d;d;f
[/TABLE]