allowed values for a field check

as a rule creator I want to be able to specify 'value in' based on an business central created 'enumeration'

tech:
Given:

FACT address
field string countryCode

enumeration created by the business in business central to prevent mistyping at rule entry: 2digitIsoCountryCodes ['AF','AX','AL','DZ','AS','AD','AO','AI','AQ','AG','AR','AM','AW','AU','AT','AZ','BS','BH','BD','BB','BY','BE','BZ','BJ','BM','BT','BO','BQ','BA','BW','BV','BR','IO','BN','BG','BF','BI','KH','CM','CA','CV','KY','CF','TD','CL','CN','CX','CC','CO','KM','CG','CD','CK','CR','CI','HR','CU','CW','CY','CZ','DK','DJ','DM','DO','EC','EG','SV','GQ','ER','EE','ET','FK','FO','FJ','FI','FR','GF','PF','TF','GA','GM','GE','DE','GH','GI','GR','GL','GD','GP','GU','GT','GG','GN','GW','GY','HT','HM','VA','HN','HK','HU','IS','IN','ID','IR','IQ','IE','IM','IL','IT','JM','JP','JE','JO','KZ','KE','KI','KP','KR','XK','KW','KG','LA','LV','LB','LS','LR','LY','LI','LT','LU','MO','MK','MG','MW','MY','MV','ML','MT','MH','MQ','MR','MU','YT','MX','FM','MD','MC','MN','ME','MS','MA','MZ','MM','NA','NR','NP','NL','AN','NC','NZ','NI','NE','NG','NU','NF','MP','NO','OM','PK','PW','PS','PA','PG','PY','PE','PH','PN','PL','PT','PR','QA','RS','RE','RO','RU','RW','BL','SH','KN','LC','MF','PM','VC','WS','SM','ST','SA','SN','CS','SC','SL','SG','SX','SK','SI','SB','SO','ZA','GS','SS','ES','LK','SD','SR','SJ','SZ','SE','CH','SY','TW','TJ','TZ','TH','TL','TG','TK','TO','TT','TN','TR','XT','TM','TC','TV','UG','UA','AE','GB','US','UM','UY','UZ','VU','VE','VN','VG','VI','WF','EH','YE','ZM','ZW']

they most likely create a data validation rule

rule "checkValidCountryCode"
dialect "mvel"
when
DeliveryAddress( countryCode not in ( "AF","AX","AL",.... ) ) <--manual comma separated entry
.....

I would like to have something like:

rule "checkValidCountryCode"
dialect "mvel"
when
DeliveryAddress( countryCode not in ( 2digitIsoCountryCodes.getEnumValues() ) )
.....