"cart"/BOL builder

I’ve asked this before but can’t find the answer I remember to be rather confusing, so lets circle back.

Is there a fairly simple way to make a ‘shopping cart’ style slice?

We are a production company and the boss is looking for something where we have 10 pallets of finished product from company A and 3 from company B. Both are going to be shipped via the same truck. or scenario B were Company A has 10 and B has 3 but they are being loaded onto 4 different trucks. He wants to be able to select specific Pallets to put on specific trucks to generate their BOLs.

My thought was something to the effect of “add rows to another table” but I need to to be multiple rows and have a ‘count down’ function (thinking plus and minus buttons). Also will need to “shipped” pallets to disappear from the selection so as to avoid duplicate shipments.

I’m open to making a separate App and then linking them together, as I have finally got most of the kinks out of our current one and don’t really want to potentially screw it up. This just has to be super low tech user capable as if it is difficult at all I think my co-workers will just stop using it.

This is confusing as I type it but I’m sure one of the geniuses in here will know what I’m trying to get at and can help. I’m happy to try and clarify as much as I can.

Thanks in advance!!!