Single BLF for multiple queues : is it possible?

Please, i’m searching for a solution to this problem:

I setup a BLF on my cisco SPA504G for queue login-logout this way

4550015700@$PROXY etc.etc.

Doing so, I’m able to login-logout from my extension 5001 to queue 5700, BLF reports the state correctly

I’ve added a second queue 5701,
By just dialing *45 on the SPA keyboard i can login-logout to both queues and BLF still reports the state correctly (extension 5001 is member of both queues)

The problem is I cannot assign the only *45 function to BLF key as
a string like *45@$PROXY on the BLF key provides the login-logout function correctly but the key becomes amber (this probably due to the *45@$PROXY is not a valid HINT on the core).

Is there a way to accomplish my need with a single button keeping BLF functionality ??

Thank you very much.