Also: "multiples separated by spaces may be OK" is a terrible phrase.
First, be definite: is it OK, or not ?  If there's uncertainty, explain what !  (Use an @note if necessary.)
Second, there are no multiples: "2*gnupg 37*openssl" nah, that'd be silly.
"Several package names, separated by spaces" is surely what you mean; if you really feel the need to phrase that as "multiple package names, separated by spaces", so be it.  (I object to this way of using "multiple"; to me it means you're asking for "double-gnupg triple-openssl", much as someone who claims to speak "multiple languages" is speaking the only multiple language I know of - double-dutch.  None the less, it appears to be a well-established usage of "multiple", at least in USAish.)