Harris radios work on Motorola P25 systems.
Motorola radios work on Harris P25 systems.
It's not uncommon for PS to have multiple systems in radios especially where there is need to interoperate. Another option, which I believe has already been in place for some time between TxWARN and LCRA, is to use what's called an Inter-Sub-System Interface (ISSI) gateway which is an APCO defined interface for such things such as easily allowing the interconnection of multiple systems, even across multiple vendors but it's transparent to the users as it is performed as a core level interconnect.