tsearch (or related) question

Hi all,

I'm looking for some tricky way for tsearch query.

Now, I know when a tsvector column has an array ('a', 'b', 'c'),
tsquery ('a&c') hits the row.

But I want to search rows with considering the order of tsvector
elements.

I want to hit a row when I use 'a&b' or 'b&c' in a tsquery,
but not 'a&c'.

Is this possible?

Regards,
--
NAGAYASU Satoshi <satoshi.nagayasu@gmail.com>