Have as many heisters in a lobby as you want! This is a beta, so you may experience crashing.
Thanks to steamtest1, polarathene, Znix, Shad0wlife and the RESTORATION Mod team for helping get this work of art working in modern PAYDAY 2.
Configure the max player amount you want in Mod Options. Defaults to 6, can go as high as 21 without crashing out for now.
Source code available: https://github.com/Crackdown-PD2/BigLobby3