per-pool routers in dhcpd.conf?

[Alexis Huxley]

Hi, I have dhcpd.conf at home containing:

	host { ... }
	...
	
	subnet 192.168.1.0 netmask 255.255.255.0 {
	    option routers 192.168.1.1;
	    option domain-name "pasta.net";
	    option domain-name-servers 192.168.1.21;
	    option ntp-servers time.pasta.net;
	
            #  1-100 are reserved for statically configured hosts.

	    #  101-150 are reserved for known dynamic hosts (known because they're in host stanzas above).
            #  e.g. my Android phone on wifi.
	    pool {
	        range 192.168.1.101 192.168.1.150;
	        allow known-clients;
	        deny unknown-clients;
	    }
	
	    #  151-200 are for unknown dynamic hosts. e.g. visitors' phones on wifi.
	    pool {
	        range 192.168.1.151 192.168.1.200;
	        allow unknown-clients;
	        deny known-clients;
	    }
	}

This works fine. 

I now want to force 'known dynamic hosts'' to use a different gateway. 

(In case you're curious: Since, when using wifi, my Android
phone silently refuses to use the DNS server proposed by the above
dhcpd.conf, I now want to change the phone's gateway to a masqueraing
Linux box, where I can hopefully use iptables to force the phone to
use the DNS server proposed by the DHCP server, and thereby block ads.)

The dhcpd.conf man page says:

	In general, any parameter can appear anywhere that parameters
	are allowed, and will be applied according to the scope in which
	the parameter appears.

and I don't see anything special documented about 'option routers'.

So I thought this should work:

        subnet 192.168.1.0 netmask 255.255.255.0 {
            #option routers 192.168.1.1;               <--- commented out at subnet level
	    ... 

            pool {
                range 192.168.1.101 192.168.1.150;
                ...
                option routers 192.168.1.32;           <--- this is the different gateway
            }

            pool {
                range 192.168.1.151 192.168.1.200;
                ...
                option routers 192.168.1.1;            <--- this is the original gateway
            }

but it looks like *no* host gets told its gateway. 

To confirm that it wasn't a problem with my new gateway itself, I
put the original gateway in *both* pools, i.e. only the *location* of
the router declaration changes compared to the original configuration:

        subnet 192.168.1.0 netmask 255.255.255.0 {
            #option routers 192.168.1.1;               <--- commented out at subnet level
	    ... 

            pool {
                range 192.168.1.101 192.168.1.150;
                ...
                option routers 192.168.1.1;            <--- this is the original gateway
            }

            pool {
                range 192.168.1.151 192.168.1.200;
                ...
                option routers 192.168.1.1;            <--- this is the original gateway
            }

The result was the same: no gateway.

My googles didn't turn up anything relevant and my experiments (using
'groups' failed), so any advice would be appreciated. I'm using 
isc-dhcp-server 4.4.1 on Debian 10. Thanks!

Alexis