What has worked for me is to "contain the Dawg" and encourage the KATs
to explore with the assurance that THAT MUTT can't "get to" them ...

SmokeMutt was pretty wired up when Boots da KAT was in sight -
Smokey spent many days FIRMLY attached to my belt with a leash.
He could approach da Kat till the leash ran out or until I reeled him back to me.
Da Kat quickly learned to *check* the THAT MUTT was in fact tethered;
and then did a rapid calculation on how CLOSE he could get ...
KAT got pretty good at flopping down about 6" OUTside of Smokey's range.

In time, Smokey learned that if he "bothered da Kat" - he'd get The Leash.
Kat built up his confidence and learned to *BOP* ta Mutt on his nose
if he got too pushy.

TWO Kats to one Dawg? --- The Kats ought to learn the Tag Team
approach to Dawg Management without too much stress.