How to compare special fields in google mock?

I have got question connected with google test. I would like to ask if while inducing "EXPECT_CALL(*A, some_method(mes1));" in test case there is possiblity to compare fields included in mes1 class.

struct Mes
{
    int a;
};

//short section of test case:
Mes mes1 = Mes();
EXPECT_CALL(*A, some_method(mes1));

I would like to ask if in google mock is a possiblity to compare special fields included in Mes. Something like:

EXPECT_CALL(*A, some_method(mes1), compare(Mes.a));//in this case google mock would compare only field "a" from Mes.