Well, that will not be mining then but it will be more like Airdropping or just a distribution that occurs every set amount of time. If you want it to be more like mining then you can set a virtual mining process that gives everyone an equal hash rate but needs a user to be logged in to get the hash set for him, this is just a suggestion.
What virtual mining sites that could you recommend in which it mines more profitable? For me it is better to participate in bounty campaign rather than Airdrop which most of it is not profitable.