You have to make and alias then bind a key to the new alias.
Create in an autoexec.cfg file
Here is mine.
echo Weapons binds and scripts
alias "main1" "use weapon_sg550;use weapon_mac10;use weapon_aug;use weapon_xm1014;use weapon_p90;use weapon_tmp;use weapon_mp5navy;use weapon_ump45;use weapon_m4a1;use weapon_awp;use weapon_g3sg1;use weapon_sg552;use weapon_scout;use weapon_m3;use weapon_m249;use weapon_ak47;use weapon_galil;use weapon_famas"
alias "main2" "use weapon_fiveseven;use weapon_usp; use weapon_glock; use weapon_deagle; use weapon_p228; use weapon_elite"
alias "pri" "main1"
alias "sec" "main2"
alias "mes" "use weapon_knife"
alias "fbgr" "use weapon_flashbang"
alias "hegr" "use weapon_hegrenade"
alias "smgr" "use weapon_smokegrenade"
alias "c4" "use weapon_c4"
bind r pri
bind w sec
bind t mes
bind g fbgr
bind v hegr
bind n smgr
bind b c4
Hope this helps.. of course this is only good for CS
D