I have the same problem.
I have a dashboard based on a one record table that no one edits. (SYS table)
This table have a global gDateFilter that is used to link with a portal record (INVOICES Table).
SYS table ----- connect to ------ INVOICES table
I have a field SYS than have a portal with INVOCES records.
The problems is that two diferent people dont can modify distint records in the portal using this relation.
Any solution?
You can see an example in this link:
https://app.easyforyouproduction.com/fmi/webd/GlobalFilter99
Thanks