if it means "taking a share" as you say

from your explanation, this is what it sounds lik: a surreptitious payment to obtain goods or services (or permits and permissions!) that otherwise wouldn't be obtainable. The Alcalde of Marbella was notorious for receiving backhanders for allowing illegal building on protected sites, and ended up in gaol, along with most of her councillors


backhander noun - definition in Business English Dictionary ...
dictionary.cambridge.org/dictionary/business.../backhanderbackhander noun - definition, audio pronunciation and more for backhander noun: ****an illegal payment or gift that is given to a person, especially someone in ...****


Backhander - Definition and More from the Free Merriam-Webster ...
www.merriam-webster.com/dictionary/ the customs official let us know that he might be ****prepared to look the other way if an appropriate backhander was slipped into ..****

Things that were linked or attached to the Ex Alcalde. Words in english that also indicate the meaning behind this use of "amarres" are "links" "attachements" possibly, "threads" as "threads" are used on the Internet today.

It indicates that the Alcade was involved, cognizant and somehow can be traced back to these things.

I would not translate it literally in this case.