I'm 'sharing' a Tram 1411 discone using a 75ohm 'cable tv' splitter, however I'm using a powered one to deal with the loss mentioned by SeanVo. On top of that, I've also got an LNA attached close to the antenna. Using this setup with trunk-recorder and 4 rtlsdr dongles (NESDR) to decode p25 as you intend to.
https://www.amazon.com/gp/product/B0082ZJNLW
I've also got all the unused F type ports on the splitter capped off with 75ohm terminators.