The vacuum source, normally a pump, is important to making the vacuum cup perform.
A single source of vacuum (one pump to one vacuum cup) is the ideal as sharing the vacuum source can cause many problems.
Specifically if one vacuum cup leaks it can inhibit or reduce the effectiveness of the other cups. If however this is not possible consider using a cluster of smaller cups mounted on a manifold that distributes vacuum equally (when one cup cannot do the job).
Furthermore, you can consider several vacuum sources and distribute the vacuum to separate cups or consider mixing the vacuum source lines - if one cup leaks it will not affect the neighbouring cup.