Systems and methods for an electronic transaction platform that enables receiving a session request for an electronic communication session over a computing network to facilitate a financial instrument transaction. The electronic transaction platform receives session attributes for the electronic communication session, which define rules and/or permissions. Based on the session attributes, a stack software object is configured for the electronic communication session to control a stack graphical user interface (GUI) during the electronic communication session to selectively operate according to a set of participation levels. An invitee selection list is received indicating selected invitees to participate in the electronic communication session, and the electronic communication session is established based on the stack software object. At least one session permission for at least one invitee computing device is selectively configured to enable the performance of a predetermined activity associated with the financial instrument transaction via the stack GUI.