"segregation between" is correct and usable in written English.
For example, you could say: "The segregation between the classes in this society is disheartening."
"He said he wanted segregation between whites and blacks.
"Income Segregation Between Schools and Districts". American Education Research Journal.
"The film portrays segregation between girls and guys, which wasn't reality.
In America the segregation between races is still deep and largely unyielding.
Professor Logan, who calculated rates of segregation between all four groups, found little change.
Past research shows that income segregation between neighborhoods increased over the past several decades.
Trophic segregation between sexes in the Black Skimmer revealed through the analysis of stable isotopes.
"Income Segregation between Schools and School District". American Educational Research Journal 53.4 (December 2016): 848-862.
But the level of segregation between blacks and Asians is almost as high as that between blacks and whites.
"These measures have broken down the segregation between children set on academic paths and those on a vocational path.
The first STEM-cathodoluminescence result shows strong impurity segregation between the CdTe and the glass.
