Is there any way of suppressing both contents weight and pressure for specific analysis?
Yes. see the following...
There are 2 popular methods to render the weight of contents to 0.00.
1. On the Static Analysis dialog, set "Fluid Density Factor" = 0.00.
or
2. Open the Analysis set, disable Contents check box
The easiest method is to set all pressure cases (P1..Pn) to 0.00. Then regardless of all settings pertaining to pressure, the load case value will always be 0.00
Static Analysis
Bentley AutoPIPE