I think you should be able to use a combination of the AUMXCONV conversion/interface table and GL162 conversion program to set up the attributes for the desired accounting units, and then use the MX500 list member population program to create a list.

We are/plan on using aumxconv to populate the attributes. I'm unfamiliar with mx500 though. After reading about it I think it provides the inverse of what we need. Though I could be wrong. We need a way to create/update lists on a scheduled batch from aumxvalue attributes.

So like...

gl20 / glnames accouting unit = 1111111111

gl20.7 aumxvalue matrix cat = division, matrixvalue = marketing

mx10 / mxlistmbr listtype=acctu, listname = mylist, attribute = division, fromval = marketing, toval=marketing

We need a way to keep that list up to date via external interface.

I think your external interface just needs to keep the attribute values updated, and you can use an automated list, probably will want to use MX123 after re-loading just to make sure, but I don't see why you would even need a manual list. If all you are doing is generating a list based on an attribute value, that's already built in...

No we cant unfortunetly...

As what if in that example above the attribute for the AU changes division = "accounting" and there isn't an "accounting" list. We'd need to create a new list programatically somehow using the division attribute where equals accounting.. That's where I was hopeing there was some type of interface into lists/mx10/mxlistmbr.

You can create the list, and based on attribute value, it will populate automatically.
Assuming the DIVISION attribute has been created on the accounting unit (ACCTU object type).
On MX10.2 : create new list for object type ACCTU; call the list ACCTG
On MX10.1, inquire on the new list (object type ACCTU; list ACCTG).
On the first row, Select 'A' for FC, select the DIVISION Attribute, and enter ACCOUNTING as the value
Click Change on the form
On MX10.2, inquire on the new list (object type ACCTU; list ACCTG), and click the Preview button.