The star pair have been linked with moves away from the Cardiff City Stadium, with Rush in particular being heavily tipped to switch to Japan at the end of the current campaign.
But despite the speculation, Young says the Blues are doing all they can to persuade the former All Blacks duo to remain in the Welsh capital.
"We are doing everything within our power to try and keep hold of them," said Young.
"There are a lot of players out of contract and our focus is the same year on year - we want to keep our best players.
"But I suppose at some stage you've got to be sensible as well."
Both back row veteran Rush and full back Blair have been in fine form once again this term and Young is desperate to see the pair commit their futures to the Blues.
But, faced with the financial clout of clubs in places like Japan and even France, Young refused to hide the fact that the numbers may not add up when it comes extending their current deals at all costs.
"It's very difficult," added Young.
"We've got to be sensible. It's a business at the end of the day and you can't pay more than you can afford.
"By the very nature of the quality of their performances they've attracted a lot of interest and a lot of big-money offers so it's a big task at the minute to try and keep all the players we've got."
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