Resolved! Application with two STM-32 MCU and one STLINK-V2 port (to one of the MCUs) - cascading possible?
An application will use two STM-32 MCUs - for purpose of this posting, I'll call them "outer" (it's SWDIO and SWCLK pins can be attached to a STLINK-V2 device for firmware downloading), and "inner" (it's SWDIO and SWCLK pins would be tied to two GPIO...