How to set quantity increments per variant in an online store?

We need to be able to set quantity increments per variant or sku within our store.

For example, one sku may need to be sold in increments of 5 and another may be 1 etc. etc.

The increment needs to be set per sku on a 1:1 level.

We are also working on integrating to our ERP and intend to have one data field per sku controlling that value.

Any suggested solutions would be appreciated.