You could implement a party of network users as an array of netuser structure. The declaration and its associated XDR routines are as shown in the following code example.
struct party { u_int p_len; struct netuser *p_nusers; }; #define PLEN 500 /* max number of users in a party */ bool_t xdr_party(xdrs, pp) XDR *xdrs; struct party *pp; { return(xdr_array(xdrs, &pp->p_nusers, &pp->p_len, PLEN, sizeof (struct netuser), xdr_netuser)); }