Sure, I wrote a demo for your use case. I assume the Sequential is considered as Seq in your network.
model = MyNetwork()
optimizer = torch.optim.SGD(
    [
        {'params': model.Seq[0].parameters(), 'lr': 0.1},
        {'params': model.Seq[1:3].parameters(), 'lr': 0.01},
        {'params': model.Seq[4].parameters(), 'lr': 0.001},
    ])
print(optimizer.param_groups)