The question is getting more complex as we deep down...
The first Soviet SAM system, that was deployed in fixed sites around Moscow, the
S-25 Berkut (SA-1 Guild) was a true multichannel system.
One battery could scan a fixed sector, track 20 targets in it, and guide one missile per target (altogether 20) parallel.
The second system, that was to be deployed around Leningrad, the
S-50 Dal (SA-5 Griffon) was also planned to be a true multichannel system.
Each battery could scan 360deg sector, track 10 targets, and guide one missile per target (altogether 10) parallel.
As we know, they run into serious trouble designing the self guiding active head of the 5V11 missile, and the project failed.
From this point, till 1979, the introduction of the S-300PT Birusa (SA-10A Grumble) system there were no Soviet multichannel* systems.
The
S-300PS Volhov M6 (SA-10B Grumble) can track 6 targets, and guide two missiles per target (altogether 12) parallel.
*In a sense, the SA-5A/B/C Gammon system is multichannel, as one site has 2~5 single channel fire control radar, so one site can track 2~5 target and launch six missile per target (altogether 12~30) parallel.