I want to allow ONLY one account of them to be the main account (by ‘main account’ I mean very specific procedure, treating that account AS IF there isn’t any other account signed along with it).
In words, at my system’s app Contacts I don’t want any contacts from those account from showing in the phone book and even in search results.
Also when one open Phone app and dial (I mean ‘hit’) some digit which has a sequence of letters (e.g. 3 with DEF) the app lists contacts containing either the digits you had hit or the the letter sequence related to these digits
(e.g. hitting [5jkl 6mno 4ghi 6mno]: all contacts having 5646 as mobile number and any contact NAMED (for example) John). Returning to the point, if the accounts are not signed in, the contacts in it (of course) won’t appear in that ‘digit search’, so is there a way to do that with multiple accounts when signed and still in just an external app I can explore these contacts (just showing them).