Copy the list of councillors into the Bcc field of your email.
Bcc hides the names from the recipients (more private, less distracting, etc)
In the "To" field, perhaps put your address or maybe the first councillor's address.

ERYC Councillors (1)

Julie@mjabraham.karoo.co.uk ; terry.allison@btinternet.com ; chrisaarnold@btinternet.com; jlbirdmolpk@yahoo.co.uk; rowan@blakejames.plus.com; mally_boatman@hotmail.com; abwarp@ukonline.co.uk; chad61@tesco.net; margaret173@btinternet.com;
doreen@clark5489.freeserve.co.uk; councillor.clubley@eastriding.gov.uk; johncox@talktalk.net; lcross@wharfe.karoo.co.uk;
janeevison@tiscali.co.uk; symon.fraser@farmline.com; coleen@sound-solutions.co.uk; helen@gilmourco.karoo.co.uk;
david@davidgrange.wanadoo.co.uk; maryrosehardy@faversham.karoo.co.uk; nev@martinst.karoo.co.uk; diana@familyhoskins.karoo.co.uk; rita@dale3.karoo.co.uk; brian.jefferies@eidosnet.co.uk; BYJefferson@aol.com; anitakay@ukonline.co.uk; mary@mlkngstn.karoo.co.uk; jeankitchen@lineone.net; lynn@highfield.karoo.co.uk

ERYC Councillors (2)
chris@matthews62.freeserve.co.uk; councillor.mcclure@eastriding.gov.uk; e.a.mccobb@hull.ac.uk; dnolan@npresearch.com;;
jvg.owen@btopenworld.net; samkeywest@aol.com; penny@hotw.fsnet.co.uk; simonbpickering@hotmail.com;
phyllispollard@hotmail.com; mark@mpreston.co.uk ; eric.raddings@talktalk.net; davidrudd@btopenworld.com;
Hilary@hsaynor.freeserve.co.uk; fred@wolfreton.freeserve.co.uk; rsl@totalserve.co.uk; gjstrouduk@yahoo.co.uk;
annsuggit@aol.com; beryleslie@yahoo.co.uk; ftemple@tesco.net; tress@tress.karoo.co.uk;
maureen@jhw.karoo.co.uk; jcw@ashcottage.fsnet.co.uk; stewart.willie@btinternet.com; polly_hornsea@hotmail.com

Copy the list of councillors (just addresses bits) into the Bcc field of your email.
Bcc hides the names from the recipients (more private, less distracting, etc)
In the "To" field, perhaps put your address or maybe the first councillor's address.

HULL Councillors (1) (Planning Ctee)

councillor.fareham@hullcc.gov.uk; councillor.allen@hullcc.gov.uk ; Councillor.brady@hullcc.gov.uk;
councillor.ellis@hullcc.gov.uk; Councillor.Chaytor@hullcc.gov.uk; councillor.fudge@hullcc.gov.uk;
councillor.j.hewitt@hullcc.gov.uk; councillor.hull@hullcc.gov.uk; councillor.mccobb@hullcc.gov.uk;
Councillor.McVie@hullcc.gov.uk; councillor.minns@hullcc.gov.uk; councillor.toon@hullcc.gov.uk; councillor.rouse-deane@hullcc.gov.uk; councillor.nicholson@hullcc.gov.uk

HULL Councillors (2)

councillor.randall@hullcc.gov.uk; ; councillor.baker@hullcc.gov.uk;
steven.bayes@hullcc.gov.uk; bird@bird.karoo.co.uk; councillor.black@hullcc.gov.uk; Councillor.Bradley@hullcc.gov.uk;
councillor.branson@hullcc.gov.uk; councillor.burton@hullcc.gov.uk; Councillor.Butterworth@hullcc.gov.uk; councillor.clark@hullcc.gov.uk; councillor.collinson@hullcc.gov.uk; councillor.garland@hullcc.gov.uk; Councillor.Gemmell@hullcc.gov.uk; Councillor.Geraghty@hullcc.gov.uk; Councillor.Glew@hullcc.gov.uk; Councillor.Gough@hullcc.gov.uk; councillor.hale@hullcc.gov.uk; councillor.harrison@hullcc.gov.uk; councillor.healand@hullcc.gov.uk; councillor.hepton@hullcc.gov.uk; councillor.hull@hullcc.gov.uk

HULL Councillors (3)

councillor.inglis@hullcc.gov.uk; councillor.jarvis@hullcc.gov.uk; councillor.larsen@hullcc.gov.uk;
councillor.lavery@hullcc.gov.uk; councillor.lowery@hullcc.gov.uk; councillor.k.neal@hullcc.gov.uk;
councillor.page@hullcc.gov.uk; Councillor.Penna@hullcc.gov.uk; Councillor.Percy@hullcc.gov.uk; councillor.brenda.petch@hullcc.gov.uk; councillor.robinson@hullcc.gov.uk; councillor.ross@hullcc.gov.uk; Councillor.Toker@hullcc.gov.uk; councillor.turner@hullcc.gov.uk; councillor.uzzell@hullcc.gov.uk;
councillor.wareing@hullcc.gov.uk; councillor.wastling@hullcc.gov.uk; councillor.waudby@hullcc.gov.uk; councillor.webster@hullcc.gov.uk; councillor.williams@hullcc.gov.uk; Councillor.G.Wilson@hullcc.gov.uk;
Councillor.David.Woods@hullcc.gov.uk