are you saying a sog seal pup knife and a leatherman knife?
or
are you saying a sog seal pup knife and a leatherman multi-tool?
my kydex knife sheath has elongated holes on both side of the sheath.
similar to this:
kydex sheath i have my leatherman multi-tool in its own nylon sheath attached with velcro bands through the belt loop of the leatherman's sheath, through the elongated holes in the knife sheath, and then secured on the back of the knife sheath.
makes for one nice, tight unit.