VBScript to increment a number for unique objects only

I posted the following in the Verticals forum for ACA but I'll quote it here as There's probably a better chance for it to be seen by the people with more knowledge of VBScripts.

Ahoy hoy. Long time no see. Unfortunately I'm popping back in because I've recently been pushed into the hinterlands outside my experience. Namely, we're finally looking into the Scheduling tools in ACA and I've been tasked with learning the property set system well enough to make them match our current workflow as closely as possible.

 

First a little background as context for my issue. I work for a small log building manufacturer using primarily ACA with a separate add-on program called HSBCad to handle creating and exporting the log tooling to the plant for production. HSBCad offers its own scripting language which functions nearly identically to C++. This scripting language was used to do many of the annotation functions as well including tagging and scheduling. Unfortunately, the in-house person who was developing our custom code left the company and we've been slowly separating ourselves from those systems to cut down on training required for new hires.

 

Yesterday I took a couple of hours to teach myself about property sets and schedules and have already created one to match our current style. With the schedule in place I've started looking into creating a tag to match ours as well. Here's where I've hit my snag. We're a bit of an odd duck in that we do not create a unique tag for each door, identical doors will receive the same tag. We do this because our buildings are shipped as 'kits' with each unique log receiving a number and it's more intuitive for the layperson that may be assembling it that the doors and windows be treated similarly. It's also easier on our own shipping and inventory management to keep human arithmetic errors out of the counts. What I am looking to do is create a formula property definition for custom door/window tags to auto-increment the number while also tagging like as like. I don't know anything about vb scripting and am new to property sets in general so I'm not sure if this is really even possible in practice.

 

TL;DR in bold

 

Edit: We're using ACA 2012

For more clarification, I need to know if it is possible to create a VBScript for a formula property definition that will create a mark number in the tag that will use an existing number if the door is identical other tagged doors an increment if it is not. The criteria used to differentiate doors are style,standard size, a user entered glazing property (tempered, low-e, etc.), hinge side, swing direction, and the wall type it is attached to.