Thank you both for your answers!
I didn't expect that "sets" was the solution to allowing access to users with a specific attribute value in their entry.
In my particular case I wanted to allow access only by users with their attribute "transactionCenterRole" set to "admin". Here is the actual statement that got me what I want:
access to filter=(objectClass=transactionCenterUser) by set="user/transactionCenterRole & [admin]" write by * read
Vladimir -- Vladimir Dzhuvinov * www.valan.net * PGP key ID AC9A5C6C
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