Auto-populate Grandchild records in grandparent view

I have a table labeled Jobs. Pretty basic. I have another table labeled units. Each User can choose from a drop-down which units are associated to the job. I've created that relationship already.

The unit is what they can choose from a drop down. So my units table can't be connected to my jobs table. I have a 3rd table now, tabbing table. This is the one that is connected to my jobs table, the user goes down and can select from a drop down all the possible units. It will then also auto-populate any other info about that unit.

What needs to happen at this point is tricky and I could use some assistance with.

Each unit has different materials associated to it that also need to show up in the job view. What's hard is each material can be used with multiple units and multiple units with multiple materials, a many-to-many relationship. 

I need the materials to just auto-populate in the job view without anyone selecting them. 

I tried the grandchild report through a report link but that doesn't work since the relationship between units and my many-to-many table can't be created due to the key field.

I hope this makes sense. Happy to share my app if someone can be of assistance as well.

Thanks!

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Nathan Allan
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