You do understand, I hope, that combining the problems in this manner produces as non-convex problem. In my view, the right thing to do is keep them separate, and run both. After all, that’s what a mixed-integer formulation is going to do anyway.
If you can provide upper bounds for vec1 and vec2 as well, then it will be possible to combine them into a mixed-integer model. But again, that will really not be any more efficient than evaluating the two of them.