May I dedicate a paper to two persons in different ages on the occasion of their birthdays? For instance, "dedicated to John on his 70th birthday, and to Steve on his 60th birthday." I appreciate it if you could help me with finding a proper sentence.
You should check the feasibility with the journal. Most of them don't like it unless the people to whom you would dedicate the work are well reputed at least in the area covered by the journal or unless the entire issue is dedicated.
Edit: the comments below the answer weren't visible to me at the time I wrote this. Otherwise I wouldn't have answered but just up voted them. Indeed, normally dedications are "to the memory". Dedications to very prominent researchers when they retire or get indeed old are even more rare.