without a slide clarifier for the 5khz shift
You'll need to change the PLL - this is a job for an expert.
The '8719 only does 10K steps, and you cant change the 10.24 crystal to give you a 5K offset because you will need at least 8 inputs to give you the coverage with 5K steps, and the '8719 only has 7.
You could overcome this by using custom made crystals and 6 switchable offsets, but that would still be an "experts only" job.
Cost of this mod would be in the $225 to $275 (AU$) range, it would be cheaper to have 2 separate rigs.
Hope this helps