All or nothing offer to one owner on 2 properties?

[Robert Alcott]

I'm considering purchasing 2 condos in a small neighborhood that is made up of multiple "duplexes" of condos. In other words, there are 2 units in every small brick house/building.

The 2 units I'm considering are in the same structure of course, and are owned by the same owner (two different deeds).

I'd prefer to get both units, and I am not really interested in only getting one of the two.

So any suggestions for how to structure an offer?

One offer encompassing both properties?

Two offers contingent on each other "Offer A is contingent upon simultaneous acceptance of Offer B?"

Any recommendations?