SEO description and announcement bar

Hi,

Fairly new to squarespace, I'm currently filling the SEO descriptions of my pages.

Before doing so, the description shown in SERP were mostly content from the pages and "sometimes" started with the text from the announcement bar.

Since I use announcement bar for special and seasonal offers, I find it relevant to see the text in some (all?) my page descriptions.

Is there any way to do something like this : 

Description : "%a. And then my custom description."

With "%a" being the current text of the announcement bar ?