multiple value validation in epmDimensionOverride

Hi experts,

is there anyway that i could do to validate multiple value in parameter member in epmDimensionOverride function?

for example:

dimension Account

ID IS_CALC

A X

B X

C X

D Y

E Y

F X

G X

C29 is cell that user can select multiple value from all available data (no restriction) by using epmContextMember

C29 contains A, B, C, D, E, F, G

EPMDimensionOverride("000", "ACCOUNT",C29)

what i want to do is filter a set of data in C29 which ONLY the value of member property IS_CALC = X

expected result is only show: A, B, C, F, G

thanks.