In an ideal world each pair would have their own grazing area with access 24/7 to a run which can be moved onto grass when required but obviously in the real worl people can have time, money and psace restraints.
Parsnipbun for example has (at the moment) all her outdoor buns housed in 12ft x8ft aviaries on concrete for safety but each pair (soon to be group) has access to the same bit of lawn daily for free range time. I don't think as far as I'm aware she has ever had issues with rabbits passing on anything nasty by sharing the same space :wave:
PS hope you don't mind me using you as an example Parsnipbun but you were the first person to spring to mind that has this to contend with.