Are there any limits as to who can issue a Circle trip ticket?

I just sent an email to the CX aus sales email address asking for a quote. I provided the fare basis and the routing/flights.

They sent back a reply saying “As Qantas is the first international carrier please contact Qantas for a quotation and ticket issuance.”

I see nothing in the rules or elsewhere on the oneworld website saying anything like this. Heck, the rules even permit AA and IB to ticket a Circle Asia, even when none of their flights can be used on that ticket.