Wordpress Galleries - Show only 4 feature images instead of the entire gallery?

Hi -I wonder if anyone can help me with this…

I have a page that has 4 Wordpress galleries on it and each gallery has approx. 30 images in each. Is there a way that I can get each gallery to display the first 4 images in that gallery only, rather than all 30 images on the page?

If this can be done by CSS that would be great - I did try the 'show one image css' as a starting point -

.gallery-item {
display: none;
}
.gallery-item:first-child {
display:block;
}'

I found it didn't really work - It did show one image but left blank spaces for the other 29 images behind it… meaning that the galleries looked very spaced out!

Thanks for any help!!
Oaksey