tsearch2: index in different table?

Is it possible to store an index in a different table? Instead of
keeping the index in a separate column, I have a separate table for
storing all indexes. I am trying to set up something like this:

UPDATE indexTable SET index1=to_tsvector('default',coalesce(Table1.Data,''));

This is currently not working, but something in this line. Is this
possible? Does tsearch2 only restrict to 1 table?

TIA