Is there any way to distinguish between targets (on the P-18 screen, for example).
I would like to know what I'm shooting at, if it's a B-52 or another type of aircraft.

Your options for non cooperating target recognition is pretty limited.
nope

In theory, comparing the plotting board to the P18 image is according to the book.
(Target type "8" on the plotting board is B52, "3" everybody else)

Another way is using our EW knowledge, due to physics, jamming metric wavelength radar is pretty space consuming.
(In short, only B52, or specialized EW aircraft could jam it. Fighters cannot.)
yep

Hpasp
Free SAM Simulator, "Realistic to the Switch"
(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/
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