mysqldump - conditional where clause with two tables ??

I am trying to get a conditional mysqldump from two related, based on
a specified relationship between the table records, and I am having
trouble constructing the statement. Here is the situation.

Two tables are involved, configured as follows:
company (
company_id,
...
)

company_site (
company_id,
site_id
)

I want to get a dump of both company records and corresponding
company_site records for a specified site_id. I tried the following
mysqldump command:

(Values in <...> are placeholders, not the actual values used)

mysqldump --user="<username>" --password="<password>"
--where="company.company_id=company_site.company_id and
company_site.site_id=<site_id>" wsadev_main company company_site >
text_company_dump.txt;

I get the following error message:
Couldn't execute 'SELECT /*!40001 SQL_NO_CACHE */ * FROM `company`
WHERE company.company_id=company_site.company_id and
company_site.site_id=<site_id>': Unknown column
'company_site.company_id' in 'where clause' (1054)

Does mysqldump have the capacity to conduct selective dumps of table
records on more than one table; and, if so, what is the proper
construction of the command?

Tim