"Temporary" Field Value?

"Temporary" Field Value?

I have a custom action in Form A report Detail View that passes the Rec ID and updates a Temp Record ID lookup field in the Form B record via openURL (and opens the Form B report in popup) .

The updated Temp Record ID field value in Form B is then used in a custom action button in the opened Form B report. After triggering the Form B report custom action, the Temp Record ID lookup field is cleared for the next user to use etc. 

The problem that I'm having is that if multiple users (let's say 3) trigger the same Form A custom action around the same time, the last user to trigger it sets the Temp Record ID value, which obviously causes problems for the other 2-users who are still seeing their Record ID populated in the Temp Record ID field. 

Does anyone know of a work-around for this? I have read how others "lock" the value so that the value cannot be updated by another user and an error message appears etc., but that won't really work in my situation as I cannot have a user waiting on another user. 

Essentially, I just need to somehow "pass" the Record ID from Form A Detail View via custom action that opens filtered Form B records....to a custom action button workflow in the Form B report records that are opened. I'm still somewhat new to Creator/Deluge so any help would be very much appreciated!