Hi Brodie.
Have you started with something that you could show us?
I don’t know how your model is built up but if you have elements with a parameter name that you set to (a,b,c,d,e,f,g) you could get the parameter value and then filter it out like they do in (How to filter string list by string) and then use a “Delete” node to delete the models that are filtered out.
Are the model groups just named a,b,c or do they inside them have a parameter value named a,b,c?
Because if they are just named a certain way you should be able to make script where you “collect” the model groups, do a filter like in the thread above and then delete.
I am not on my PC now but will check in Dynamo later.