Log Shipping - two secondary databases for the same primary on same instance?

Hi

I know it might not make too much sense, and isnt really the intended use (considering the wording on books online) - but does anyone know of a way to be able to have two logshipping secondary databases configured on the same instance of sql server (for the same primary database, that is)?

I have tried it, but when i run sp_add_log_shipping_secondary_primary, i get an error saying that i already have an entry for the primary server/database.

Msg 32024, Level 16, State 1, Procedure sp_add_log_shipping_secondary_primary, Line 95
An entry for primary server [servername], primary database [primary database name] already exists.