Not true. You can lock out or avoid a site in a lot of scanners directly or through their software. This will sometimes help with simulcast issues, but not always.
Yes, you can lock out a "site" but a site does not always equal a single, specific tower. In a simulcast system, a site usually contains multiple towers, and those towers share the same set of frequencies. As an example, look at the FCC data for the CCCO West Simulcast Site site in the EBRCS system:
WQLV705 (CONTRA COSTA, COUNTY OF) FCC Callsign Details Within that single site, there are multiple locations (towers) in El Cerrito, Richmond, Hercules, and Crocket that use the same frequencies.
In that list, there seems to be one oddball tower at Clayton - maybe that one is from another site that got lumped in with this FCC license; I'm not sure.
This is the RR page showing the shared frequencies for that particular site:
CCCO West Simulcast Site Details (East Bay Regional Communications System (EBRCS))
If you know of a way a scanner can lock out all but one of those El Cerrito, Richmond, Hercules, or Crocket towers, please let me know - I'd love to be able to do that with a simulcast system in my area.
In many cases you will also have to attenuate the system signal to try and only get one signal and/or use a directional antenna for the same purpose.
Yes, that is a tactic to isolate the signal to a single tower within a simulcast site.
Trying to receive a simulcast system often involves using the lousiest antenna you can find to limit the reception of more than one source of signal if its a strong system or you are in thr middle of a bunch of towers. No scanner, including the x36 Uniden scanners can handle this any better than any others. Its all a function of location, signal strength & directional receiving techniques.
Might want to check out this video making a comparison of a couple of other scanners to a BCD536hp on a simulcast system. The best results came from a combination of the BCD536hp and a directional antenna:
https://www.youtube.com/watch?v=PXS7TofSnxk
There is only so much I can say about the x36hp scanners because I don't own one. I'm basically relying on what I hear from some of their owners and kinda passing that along. I just want the OP to have as much knowledge as possible.