Check entry zip code

Hello,

I would like to know if it is possible to:
Check for excisting zip-code. In the Netherlands we have zip codes like AAAAXX0 or AAAAXX00 or AAAAXX000 Is it possbile to create a check for this in the zip code field?
Also, I need to check if an other subsciber has already used this zip code. Only one membership per zip code is allowed.

Regards, Peter

Hi Peter

For this, you will need to develop your own validation rule, so basically, needs programming skill for this development

See membershipprodoc.joomservices.com/basic-...ld-custom-validators

Tuan