filter for leading special characters

I have a site that is generating help page links dynamically. Unfortunately I have no control over what it uses for a link (these are dynamically generated by the system and programmed by someone else).
I’m using Custom Permalinks to enable the use of posts for help topics based on these links. One of my permalinks that I’m trying to create is /-Individual-GridObjectList_ext.html
The challenge I’m having is, this awesome plugin is stripping the ‘-‘ at the start of this (so it becomes /Individual-GridObjectList_ext.html which results in a 404). Would it be possible to provide a filter (as you have for many other options including Uppercase handling) to allow this ridiculous but necessary request?
Thank you for your consideration.