in codebehind class, i collect certified roles?

i have following web.config:

<location path="restrictedpage.aspx">
    <system.web>
        <authorization>
            <allow roles="group1admin, group3admin, group7admin"/>
            <deny users="*"/>
        </authorization>
    </system.web>
</location>

within restrictedpage.aspx.cs, i collect certified roles collection contains group1admin, group3admin, group7admin?

here's since i ask:

the web.config doing authorisation page. works fine. nonetheless i'm going have integrate pages (say restrictedpage.aspx, restrictedpage2.aspx, restrictedpage3.aspx). any pages going have tradition webcontrol it. any pages have opposite certified roles. webcontrol dropdown list. choices within dropdown count intersection user's roles page's certified roles.

as mentioned below, poison web.config xpath substantially work. i only anticipating something some-more framework-y. kind sitemap. i put roles web.sitemap, i squeeze controlling sitemap.currentnode.roles (my website controlling windows authentication, i can't web.sitemap confidence pleat i'd rather say roles wholly file).