Theoretically speaking, this is not consistant, because if you move through one portal, you need to come out at another time through [another] portal. This would all happen faster than light, in a subreality which you cannot set up another portal. You would first need to move through spacetime, set up two portals, lightyears away, only then can you move through one portal, and hope to come out of the other end, which is also another seperate portal.