Members of a task force proposing regulations for recreational marijuana in Colorado approved recommendations Tuesday that would allow for marijuana tourism but block out-of-state pot shop owners.

The Amendment 64 Implementation Task Force voted to allow people from outside of Colorado to shop in forthcoming retail marijuana stores, though the amount they could purchase at any one store would be limited.

The goal is to prevent “smurfing,” which would occur when one person goes from store-to-store accumulating marijuana to then sell into the black market. The thinking is that lowering the amount of marijuana an out-of-stater could buy in any one store would make smurfing too time-consuming to be worthwhile.

30 QUESTIONS: Answers to frequently asked questions about Colorado’s pot legalization

The task force also approved recommendations that recreational marijuana stores only be owned by Colorado residents. People would have to live in the state for two years to be considered residents.

And the task force voted to recommend that recreational marijuana stores be vertically integrated – meaning they would have to grow most of what they sell – for at least the first two years. In addition, only medical-marijuana dispensary owners would be able to apply to open recreational marijuana stores for the first year. Applications for recreational pot shops will be accepted starting later this year.

Amendment 64 legalized limited possession and retail sales of marijuana for people 21 and older. The task force has until the end of the month to recommend rules for how that should work. Legislators will then cobble together laws for the new recreational marijuana regime.

The first recreational marijuana stores are expected to open at the beginning of next year.