I did my graduate studies in Mathematics at two completely different universities, A and B, from my country. During my studies from university A, I had a very good professor X in theoretical statistics. In my studies from university B, I had a very good professor Y in stochastic calculus. Professors X and Y do not know each other and have not worked together before. Moreover, although both belong to a statistics department, their areas of research are not exactly the same. University A is good and is near my home. University B is top ranked and far from my home.
In my country, opportunities of job at university for young researchers are little, so doing a PhD at two different universities would certainly enlarge my possiblities for a job in the future. My question is whether it would be acceptable to pursue a PhD at university A with advisor Y and co-advisor X. I mean, is it acceptable to do most of the part of the thesis with professor Y and some research with professor X, although both areas of research are not exactly the same, but both are from a statistics department?