How can i create sequential id

Hi,

I need to create an id for each new record. I have four tables that each contain information about a different type of customer.

I need the ids to be sequential across all of the tables. For example, if the last id assigned was xyz-12-001, the next id, no matter which table it is for, needs to be xyz-12-002.

The "xyz" will be the same for every id and the "12" is the last two digits of the year. The last 3 digits need to increase by 1 with each new id.

Can anyone help me with this??