trying to connect trunked HP to VLTed Dell switches without a loop

Hello networking,

I just can't wrap my head around this scenario:

The Dell 02 Switches needs a link to HP 02 to get some redundancy.

Dell 01 and 02 are connected via VLT interconnect.

But HP 01 and 02 are only connected via a simple trunk. So no switch-interconnect or the like.

HP 01 and Dell 01 are already connected. But connecting HP 02 and Dell 02 will create a loop, wouldn't it?

But how to prevent? Was already thinking about a LACP port-channel on the Dells. But what to do then on the HP side? Or is that BS anyways?

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+-----------------+ VLT Interconnect +-----------------+ | Dell 01 |<-------------------->| Dell 02 | | | | | +-----------------+ +-----------------+ ^ | v +-----------------+ +-----------------+ | Procurve 01 | Simple Trunk | Procurve 02 | | |<-------------------> | | +-----------------+ +-----------------+