Why would you be seeking parity to Qantas when it is another airline and another company? Just because it is part of the 'Group', does not mean that all conditions should be aligned across all airline groups. They don't for many parts of the business, and for good reason (mostly cost). If this 'benefit' is desired - then why not join Qantas? JQ is an LCC, so, their 'conditions' reflect that of an LCC. I am not sure why there is this mentality.
There are career/employment benefits for working at JQ and there are career/employment benefits for working at QF. And this replicates around the world. Personally - you are better off focussing on the things that really matter to you, and defending those. Not throwing all the 'other airlines benefits' into the basket, especially something like 'lounge', which has such little materiality.
Have a few, meaningful terms and conditions versus a laundry list of 'match this and match that'... My view anyway...