Microsoft Project? You probably meant Microsoft SQL Server, the
enterprise-level database system. That is certainly a good option if
you have that much data, but 35 users (if they are CONCURRENT) means
that the app will only work well if developed by a strong Access
developer. Reason is that this is somewhat outside of the design
parameters of MsAccess, so you'll need a strong professional touch to
make that happen.
SQL Server also comes with its learning curve, but that's manageable
compared to the required quality of the Access programming. It may be
time to search your Yellow Pages for "Microsoft Solution Provider".
-Tom.
Microsoft Access MVP