Using nested iterators to merge combinations of feature classes

[ttw_marine]

I have a gdb with different polygons (buffers) in. I want to create all of the different combinations when two of these polygons are merged. I have tried to achieve this with 2 nested iterators, but so far having some issues.

One issue I have found is only 1 output / combination is created in the gdb, as if the iterator isn't working at all. My latest attempt causes the tool to run infinitely (it seems!!), and I can see there is only one combination of buffers being created / merged in the dialogue pane and in the folders through file explorer. 

Model 1: iterate through feature classes in gdb, merge with different iterated outputs of nested model.

v2Buffs1: iterate through feature classes in gdb, outputs to be used in main model merge

Any help much appreciated! Happy to explore options using Python if easier?

[Robert_LeClair]

As you likely know, a model can only have one iterator but you can get around this by working with a model within a model as referenced here.  I also worked with a customer that kind of got around the one iterator per model issue by having 3 models that were then accessed via a Python script tool.  You can read about it here.