Once connected the identifier for the asset (1) is carried to the next asset (2). The connected parts return a number (1+2) and the resulting value (3). There would be a trigger for this specific return value on this connector.
Could be a true/ false parameter.
The asset would fetch the part ID and either report the ID exists or allow to generally say if there´s something connected to it. Eventually the parameter with the ID of the connected part would be there already and would just change to a different value when another asset is connected, thus changing either the total in a calculation or trigger the true/ false parameter.