El Camino: how to maintain the proper enrollment for employees that move from benefit eligible to per diem (not benefit eligible)

Hi All,
I was talking with ECH today and they are wondering how we can maintain the proper enrollment for employees that move from benefit eligible to per diem (not benefit eligible) and vice versa.

The issue is that Benefit Eligible employees get benefits at 16 hours. So it is not automatic that they would be considered FT for ACA purposes. ECH measures hours for all employees though PeopleSoft. So there can be a case when someone is Benefits Eligible is an FT under ACA and then moves to Per Diem and so they should not lose benefits. But as provided in earlier messages ECH has different ACA classes.
1) Value = ACA-A: This is for per diems who are eligible to enroll themselves, their child(ren) and their spouse in Medical.
2) Value = ACA-B: This is for temps based on FTE who are eligible to enroll themselves and their child(ren) in Medical. No spouse enrollment.
3) Value = ACA-C: This is for temps and per diems who are eligible to enroll themselves and their child(ren) in Medical. No spouse enrollment.

So note that an employee can go from Benefits Eligible to Per Diem but be an ACA FT so still eligible for coverage but now their spouse may no longer be eligible because they now have to move into the ACA coverage as a Per Diem.

The other way around a person can be Per Diem and eligible as an ACA and then move to Benefits Eligible so now their spouse can be enrolled.

So I need to know what they need to send us to make this happen. I think an hours worked number for all and then I think we also need a flag or something so that we know to send a COBRA letter to the spouse when they lose eligibility when the employees is ACA and moves to per diem under B or C class above. The classes a person is eligible for is based on their union.