Check and see if the columns of pasted text are separated by tab characters. If so, you can use the inspector to set tab stops on this field as long as text inside the cells does not have to wrap to second line within the cell.
Alternatively, a script could parse the pasted data into separate fields and records of a related table such that a portal can be used to produce your table.
The data could also likely can be displayed in a web viewer.
It's not the form the data takes in the original document that's key, but rather what form the data takes after pasting into a field in FileMaker.