Yes. Nothing stops you bidding in two shows, or in a show and a timed auction at once.
The practical problem is not the bidding. It is winning.
What happens if you win both
Two wins are two separate orders, each with its own payment clock. Watching when you won means thirty minutes — for each.
So winning two things in the same ten minutes means paying for two things in the same half hour. If you cannot, one lapses, and a lapsed win is a strike. Three strikes in ninety days and you cannot bid for a while. What happens if I don't pay.
Why delivery does not combine across shows
Items from different stores are always separate parcels, separately charged. There is no version of this where two shows become one delivery.
Within one store, combining is the seller's setting rather than a rule — many do combine, so winning three things from one seller is often one parcel.
The practical advice
Bid seriously in one show at a time. Watch the other if you like, but do not bid in both unless you can afford to win everything you have a bid on.
The failure mode is specific and common: someone bids on four items expecting to win one, wins three, and pays for two. The third becomes a strike on an account that did nothing wrong except underestimate its own luck.
If you do win more than you can pay for
Pay for the ones you want, in order of what you want most. Let the rest lapse rather than paying for something you did not want — but know that each lapse is a strike, so this is damage control rather than a plan.
The better move is a maximum bid on the one item you actually want, and watching the rest. What a maximum bid is.
More: how long do I have to pay, what happens when you win, how delivery is charged.