Yes, there is a way to increase the number of requirements allowed in a baseline.
On page 191 of the HP ALM 11.52 Administrator Guide, you will see the following:
REQUIREMENTS_LIBRARY_FUSE
This parameter indicates the maximum number of requirements for a
library in order to maintain optimal performance.
The default value for this parameter is 3500. A validation of this value
is performed when you create baselines, import libraries, or
synchronize libraries.
So, you will need to go to Site Administration and increase that parameter from 3500 to 10000 if that is your upper limit.