you might consider an interactive container field and insert a PDF if you want to be able to copy individual values from this table. And I've heard of a plug in that can import data from a PDF file...
Instead of copy/paste, you could set up an import records script that imports the data into a set of related records that you display via portal. Depending on the data pasted, a script might be able to parse the pasted data into such a table for portal display.
And if the columns of data paste with tab characters separating the columns, you can use the appearance tab in the inspector to set tab stops to establish uniform columns of the pasted data inside this field.
Thanks very much for taking the time.